In the sentence "Cybercrime cases pose various kinds of challenges which requires strengthening of the institutional mechanism", which numbered part contains the grammatical error?

Introduction / Context:
This error spotting question is about subject verb agreement in a relative clause. The sentence describes how cybercrime cases present various challenges and the need to strengthen the institutional mechanism. You must identify which numbered part of the sentence contains the grammatical mistake.

Given Data / Assumptions:

• Part 1: Cybercrime cases pose various kinds of
• Part 2: challenges which requires strengthening of
• Part 3: the institutional mechanism.
• Part 4: No error.
• The antecedent of which is challenges, which is plural.

Concept / Approach:
The verb in the relative clause which requires must agree with its antecedent challenges. Since challenges is plural, the verb should also be plural: require, not requires. The rest of the sentence is grammatically sound, so the error lies in the second part, where a singular verb has been used for a plural subject.

Step-by-Step Solution:
Step 1: Identify the main structure: Cybercrime cases pose various kinds of challenges...Step 2: Recognise that the relative pronoun which refers back to challenges, a plural noun.Step 3: Look at the verb inside the clause: which requires strengthening of.Step 4: Apply subject verb agreement: a plural subject (challenges) needs a plural verb (require), not requires.Step 5: Conclude that part 2 has the error and should read challenges which require strengthening of.

Verification / Alternative check:
Rewrite the sentence correctly: Cybercrime cases pose various kinds of challenges which require strengthening of the institutional mechanism. Now the plural subject challenges matches the plural verb require. Parts 1 and 3 are grammatically fine: pose is correct for the plural subject cybercrime cases, and the institutional mechanism is a proper noun phrase. Part 4 No error cannot be right because we have found a clear subject verb disagreement in part 2.

Why Other Options Are Wrong:
Part 1 uses the verb pose with a plural subject and is correct. Part 3 simply provides the object of strengthening and does not contain any verb that might disagree. Part 4 suggests no error, but the agreement problem in part 2 shows that there is indeed an error in the sentence.

Common Pitfalls:
Some students focus only on the main clause and miss agreement issues in relative clauses beginning with which, who, or that. A good exam strategy is always to check each clause separately, making sure that the verb agrees with the noun it really refers to, not with a closer but unrelated noun. Here, the proximity of which to requires may distract you from checking its connection with challenges.

Final Answer:
The grammatical error occurs in part 2, where requires should be require, so option B is correct.