In each of the following questions, find out which part of the sentence has an error. The sentence is divided into three parts labelled A, B and C, and part D indicates that there is no error. Identify the part that contains a grammatical or usage error in the sentence: The police have arrested the thief who broke into my house last night.

Introduction / Context:
Error spotting items test whether you can distinguish correct English sentences from those containing subtle mistakes. In this question, the sentence about the police arresting a thief is divided into parts to help you focus on each segment. You must decide whether any part contains an error in tense, agreement, or structure, or whether the sentence is entirely correct and therefore should be classified as having no error.

Given Data / Assumptions:
- Full sentence: The police have arrested the thief who broke into my house last night. - Part A: The police have. - Part B: arrested the thief. - Part C: who broke into my house last night. - Part D: The sentence is grammatically correct; no error.

Concept / Approach:
The key grammatical points to check here are subject verb agreement, correct tense usage, and correct placement of modifiers like last night. In standard English, the word police is treated as a plural noun when referring to the police force in general, so it takes a plural verb have. The present perfect tense have arrested is appropriate for an action whose result is relevant to the present. The clause who broke into my house last night correctly modifies the thief. If all these aspects are correct, the answer is that there is no error in the sentence.

Step-by-Step Solution:
Step 1: Examine part A, The police have. The subject police is plural in this sense, and the plural auxiliary have is therefore correct. Step 2: Examine part B, arrested the thief. This verb phrase completes the present perfect tense have arrested and correctly states the action performed by the police. Step 3: Examine part C, who broke into my house last night. This is a defining relative clause describing the thief and uses the simple past broke, which is appropriate for an action completed last night. Step 4: Confirm that last night refers to the time of the breaking in, not necessarily the time of arrest, and its position in the clause is acceptable. Step 5: Since all parts are grammatically sound and idiomatic, the only accurate choice is that the sentence has no error.

Verification / Alternative check:
To verify, you may rewrite the sentence as one unit and compare with typical English usage: The police have arrested the thief who broke into my house last night. This structure is commonly seen in newspapers and spoken English. There is no subject verb disagreement and no tense mismatch between arrested and broke. The phrase last night clearly attaches to broke into my house and does not create ambiguity that makes the sentence wrong. Therefore, declaring no error is fully justified.

Why Other Options Are Wrong:
Part A is not wrong because police correctly takes the plural auxiliary have in this context. Part B is not wrong because arrested the thief is a correct verb object combination. Part C is not wrong because the relative clause who broke into my house last night is grammatically and logically sound. Part D is right to state that the sentence is grammatically correct and free from error.

Common Pitfalls:
Some learners mistakenly think that police should always be treated as singular or that last night must appear at the end of the entire sentence. Such rigid views lead to incorrect identification of errors. In English, many collective nouns, including police, can be treated as plural when referring to the group as a collection of individuals. Also, adverbials of time are flexible in position as long as the meaning remains clear. Being aware of standard patterns in reading material helps you avoid overcorrecting correct sentences.

Final Answer:
The correct response is The sentence is grammatically correct; no error.