In SAP Materials Requirements Planning (MRP), a source of supply (for example, a contract, scheduling agreement or info record) can be assigned automatically during the MRP run. Which of the following is a key system prerequisite that must be fulfilled so that source determination can take place during the MRP run itself?

Introduction / Context:
In SAP Materials Management and Production Planning, the MRP run can automatically determine suitable sources of supply, such as contracts, scheduling agreements or purchasing info records. This automation is only possible if certain configuration and master data prerequisites are met. The question focuses on the specific system setting that enables the MRP program to perform source determination during the planning run, rather than relying purely on manual assignment in purchasing.

Given Data / Assumptions:

• The planning run is an MRP run carried out in SAP for materials planning.
• The system can determine sources of supply such as contracts, scheduling agreements and info records.
• The question asks about a key prerequisite for source determination during the MRP run itself.
• Other conditions such as contracts, quota arrangements and source lists may exist, but the focus is on what must be activated at run time.

Concept / Approach:
Automatic source determination in MRP depends both on master data (for example, source list records and info records) and on system control parameters that tell the planning run whether to use that information. In the MRP run selection screen and customizing, there is a setting that activates source determination. If this function is not switched on at the time the MRP run is started, the system does not attempt to assign sources of supply automatically, even if all master data prerequisites are in place. Therefore, we look for the option that explicitly mentions activation of the source determination facility for the MRP run.

Step-by-Step Solution:
Step 1: Identify what it means to assign a source of supply during MRP. This means that when the system creates planned orders or purchase requisitions, it automatically links them to a contract, scheduling agreement or other source object.Step 2: Recall that source determination is controlled by a specific setting, both in customizing and on the MRP run settings, which must be activated when the run is executed.Step 3: Check option B, which states that the source determination function must be activated at the start of the MRP run. This matches the required system level prerequisite.Step 4: Review options A, C and D and note that they describe master data related conditions (contract indicators, quota arrangements, info records and source list flags) which may influence which source is chosen but are not the runtime switch that enables the determination at all.Step 5: Conclude that option B is the most accurate answer to the question about prerequisites for source assignment during the MRP run.

Verification / Alternative check:
In SAP documentation and configuration, you can find the control that enables or disables source determination during MRP. When it is deactivated, the MRP run still plans requirements but leaves the assignment of sources to follow on manual purchasing activities. When it is activated, the system reads valid sources (for example, source list entries and quota arrangements) and assigns them automatically to the generated procurement proposals. This confirms that the runtime switch described in option B is essential.

Why Other Options Are Wrong:
Option A (MRP relevant indicator in a contract) influences whether a specific contract can be considered, but without activated source determination, the contract is never evaluated during MRP. Option C (quota arrangement setup) controls how quantities are split between sources but does not itself start source determination. Option D (info record plus single source flag) is important master data but still requires the MRP run to actively perform source determination. These are useful conditions, but they are not the prerequisite that the question asks for.

Common Pitfalls:
A common mistake is to assume that good master data alone guarantees automatic source assignment. In reality, configuration and runtime parameters must also instruct the MRP run to use that data. Another pitfall is to treat every condition listed in training material as mandatory, rather than recognizing that some are optional refinements, such as quota arrangements. For exam style questions, always differentiate between system switches that enable a function and data conditions that influence which result is chosen once that function is active.

Final Answer:
The key prerequisite is that the source determination function must be activated when the MRP run is started.