In the following sentence, identify the part that contains a grammatical error: "Me and my wife were at home last night."

Introduction / Context:
This error detection question examines correct use of personal pronouns in the subject position of a sentence. In formal English, subject pronouns such as I, we, he, she, and they should be used as subjects. The sentence uses a phrase that sounds informal in conversation, and you must identify which part is grammatically incorrect for standard written English.

Given Data / Assumptions:
The sentence is divided into parts:

• A: Me and my wife
• B: were at home
• C: last night.
• D: No error

We are assuming formal examination style English.

Concept / Approach:
In English grammar, the pronoun used as a subject must be in the subjective or nominative case. Me is the objective form, used after prepositions or verbs. In the subject position we should use I. Additionally, polite convention suggests mentioning the other person before oneself, so the preferred phrase is my wife and I. The rest of the sentence, including the verb were and the adverbial phrase last night, is correct.

Step-by-Step Solution:
Step 1: Identify the subject phrase. The subject is Me and my wife. Step 2: Check pronoun case. Me is an object pronoun and should not be used as part of the subject in formal English. Step 3: Replace Me with the subject pronoun I. The grammatically correct pair would be My wife and I. Step 4: Confirm the verb. With a compound subject My wife and I, the plural verb were is correct. Step 5: The phrase at home last night functions as an adverbial of place and time and is acceptable. Step 6: Therefore, the grammatical error lies in part A, Me and my wife.

Verification / Alternative check:
Rewriting the sentence as My wife and I were at home last night makes it suitable for formal writing and examination standards. You can also test by removing one half of the compound subject. You would never say Me was at home in standard English. You would say I was at home, which clearly shows that I is the correct subject pronoun.

Why Other Options Are Wrong:
Option B, were at home, is correct for a plural subject like my wife and I. Option C, last night, is a normal time expression and has no grammatical problem. Option D, No error, is wrong because there is a clear mistake in the subject pronoun form in part A. Thus only part A contains the error.

Common Pitfalls:
In everyday speech many people casually use expressions such as me and my friend. Learners sometimes transfer this informal pattern into formal writing and examination answers. Another pitfall is forgetting the polite order of mentioning other people before oneself. To avoid errors, remember that subject pronouns are I, we, he, she, and they, and that it is better style to say my friend and I, my parents and I, or my wife and I.

Final Answer:
The incorrect part is Me and my wife, that is, part A.