In the following question, a sentence is divided into four parts which are labelled A, B, C, and D. One of these parts may contain an error in grammar or usage. Identify the part that has an error. If there is no error, select the option that states that the sentence is correct. The Directors are (A) / now inquiring (B) / in the cause of the fire. (C) / No error. (D)

Introduction / Context:
Error spotting questions test a learner ability to identify mistakes in grammar, vocabulary, or usage within a sentence. Here, the sentence describes Directors who are investigating the cause of a fire. The sentence is divided into four labelled parts so that we can indicate exactly where the error lies.

Given Data / Assumptions:
The sentence is broken up as follows.

Part A: The Directors are
Part B: now inquiring
Part C: in the cause of the fire.
Part D: No error.
We must find which part contains incorrect usage.

Concept / Approach:
The key verb phrase here is inquire into something, which means to investigate or examine a matter carefully. In standard English, we do not usually say inquire in the cause; instead, we say inquire into the cause. The preposition into is used because it conveys the idea of looking deeply inside the matter. Therefore, the error lies in the wrong preposition in Part C, where in is used instead of into.

Step-by-Step Solution:

Verification / Alternative check:
We can verify by rewriting the sentence correctly: The Directors are now inquiring into the cause of the fire. This version sounds natural and matches typical usage found in formal reports or news articles. No changes are needed in Parts A and B, and Part D, No error, is therefore incorrect as a response choice, because we have already identified a grammatical problem in Part C. This confirms that the error lies specifically in the preposition in.

Why Other Options Are Wrong:
Part A is correct, because The Directors are is a proper way to begin a sentence about multiple directors. Part B is also correct, because now inquiring accurately combines the adverb now with the present continuous participle inquiring. Part D, which represents No error, cannot be correct because we have seen that the preposition in in Part C should be into. The option More than one part has an error is also wrong, since Parts A and B are fine and only Part C needs correction.

Common Pitfalls:
Many learners overlook small preposition errors, especially when the sentence seems generally understandable. Another pitfall is to misidentify the error as being in the main verb inquiring rather than in the preposition that follows it. To handle such questions effectively, it helps to learn common verb plus preposition combinations, such as inquire into, look into, and comment on. Recognising these collocations quickly makes it easier to spot incorrect prepositions in exam sentences.

Final Answer:
The error is in Part C, which should read into the cause of the fire instead of in the cause of the fire.