In the following sentence, one part may contain an error. Identify the part with the error; if the sentence is correct, select "No error": Hardly had I reached the (1) / exhibition where I learnt (2) / about the major robbery. (3) / No Error (4).

Introduction / Context:
Error spotting questions often check the correct use of correlative structures in English, such as hardly... when..., no sooner... than... and so on. In this sentence, the expression begins with hardly, which normally pairs with when or before, not with where. Recognising the correct pair helps in identifying the exact part of the sentence that contains a grammatical error.

Given Data / Assumptions:

• Sentence given: Hardly had I reached the (1) / exhibition where I learnt (2) / about the major robbery. (3) / No Error (4).
• Part 1: Hardly had I reached the.
• Part 2: exhibition where I learnt.
• Part 3: about the major robbery.
• The intended meaning is that the speaker had just reached the exhibition when he or she learned about the robbery.

Concept / Approach:
The correlative pattern with hardly is usually hardly... when or hardly... before, meaning that as soon as one action was completed, another one happened. In the sentence, where is used instead of when, which is incorrect because where refers to place, not to the time relationship between two actions. The correct form should be Hardly had I reached the exhibition when I learnt about the major robbery. Therefore, the error lies in the segment that contains where.

Step-by-Step Solution:
Step 1: Identify the correlative construction: the sentence opens with Hardly had I reached.
Step 2: Recall that this structure requires when or before to introduce the second action.
Step 3: Look at the next part and see exhibition where I learnt, which uses where instead of when.
Step 4: Recognise that where indicates place, not the correct time relation, so it is inappropriate here.
Step 5: Conclude that part 2 contains the error and that where should be replaced by when for correct usage.

Verification / Alternative check:
Replace where with when and read the corrected sentence: Hardly had I reached the exhibition when I learnt about the major robbery. This version clearly and correctly expresses that the learning happened almost immediately after arriving. If we try to leave where in place, the sentence seems to suggest that the exhibition is the place where learning occurs, rather than highlighting the quick succession of events. Since the question is designed to test the hardly... when pattern, the presence of where in part 2 is clearly wrong.

Why Other Options Are Wrong:
Part 1, Hardly had I reached the, correctly uses inversion with hardly and sets up the structure. Part 3, about the major robbery, is grammatically sound and provides the object of learnt. Part 4, No Error, is only a label for the case where no error exists, which is not true here because we have already identified an error. Therefore, only part 2 is grammatically incorrect, making option B the correct answer.

Common Pitfalls:
Learners sometimes mix up similar patterns such as hardly... when and no sooner... than, leading to combinations like hardly... than or no sooner... when, both of which are wrong. Another mistake is focusing only on vocabulary and overlooking these small but important linking words. To avoid such errors, it is useful to memorise a few fixed examples for each pattern and to consciously check them when doing error spotting exercises.

Final Answer:
The error is in part 2; the sentence should use when instead of where after hardly had I reached.