Multiplexer control principle: Evaluate the statement — “In a multiplexer (MUX), the data-select control inputs determine which data input is forwarded to the single output line.”

Introduction / Context:
A multiplexer (MUX) is a fundamental component that funnels one of many inputs to a single output. Understanding that the select lines act like a binary address to choose the active input is essential for designing bus interfaces, data acquisition systems, and communication paths.

Given Data / Assumptions:

• Digital MUX with N inputs, one output, and log2(N) select lines.
• An enable pin may gate the device but does not change the core selection rule.
• All inputs are compatible with the MUX’s logic family.

Concept / Approach:
For a 2^n-to-1 MUX, the n select lines encode a number from 0 to 2^n - 1. That code chooses the corresponding input channel. This behavior holds across digital and analog multiplexers; enable simply allows or disables the output drive.

Step-by-Step Solution:

Verification / Alternative check:
Examine a timing diagram for a 4-to-1 MUX. Changing select S1 S0 from 00 to 01 immediately routes I1 to the output. Oscilloscope measurements confirm the selection behavior.

Why Other Options Are Wrong:

• Incorrect: Contradicts the fundamental purpose of a MUX.
• Only true for analog multiplexers: Digital MUXs work the same way regarding selection.
• Only true when enable is LOW: Enable polarity varies by device; selection logic is independent.
• Parity-protected inputs: Parity is unrelated to selection.

Common Pitfalls:
Confusing enable with selection; miswiring select order (endianness); ignoring MUX propagation delay and bandwidth limits.

Final Answer:
Correct