In the following sentence, some part of the sentence may have an error. Identify the part that contains an error, or select "No error" if the sentence is grammatically correct. Sentence: Since they were all dressed up, she assumed they were going to church together.

Introduction / Context:
This question tests your ability to spot grammatical errors in a complex sentence. The sentence is divided into labelled parts A, B, C and D, where D stands for "No error". You must determine whether any grammatical, tense or agreement mistake exists, or whether the sentence is already correct as it is written.

Given Data / Assumptions:

• Part A: Since they were all dressed up,
• Part B: she assumed they
• Part C: were going to church together.
• Part D: No error.
• We assume that punctuation marks are acceptable and that the question is about standard English grammar, not style.

Concept / Approach:
The sentence describes a past situation and a past assumption. All verb forms therefore need to be in the past, with proper subject verb agreement. The conjunction "since" introduces a reason clause. The expression "dressed up" is idiomatic and correct. The phrase "were going to church together" correctly expresses a past intention or plan. The reported belief "she assumed they were going" is a normal reported speech structure in the past. If all these checks pass, then the correct answer must be "No error".

Step-by-Step Solution:
Step 1: Check the tense sequence. The verbs "were", "assumed" (understood) and "were going" all refer to past time, which is consistent and grammatically correct.Step 2: Inspect part A, "Since they were all dressed up". "Since" introduces cause, "they" is the plural subject, and "were" is the correct plural past form. "Dressed up" is a standard phrasal adjective meaning wearing formal or special clothes. No error here.Step 3: Inspect part B, "she assumed they". The subject "she" and verb "assumed" (understood in context) form a grammatically correct past tense clause.Step 4: Inspect part C, "were going to church together". The plural subject "they" correctly takes "were going", and the phrase "to church together" is idiomatic and meaningful.Step 5: Because parts A, B and C are all grammatically correct and express a clear meaning, the appropriate choice is part D, "No error".

Verification / Alternative check:
Try rewriting the sentence without labels: "Since they were all dressed up, she assumed they were going to church together." Native speakers would accept this sentence without hesitation. There is no mismatch of tenses, no missing article, and no incorrect preposition. Reading it aloud confirms that it flows naturally.

Why Other Options Are Wrong:
Choosing A, B or C would imply that there is some hidden error in those parts. However, there is no justification for changing "since they were all dressed up", "she assumed they" or "were going to church together". Any attempted correction would either shift the tense unnecessarily or break an idiomatic expression.

Common Pitfalls:
Some students feel that every error spotting question must contain an error, so they choose something to change even when the sentence is correct. In many examinations, some sentences are intentionally error free to test whether candidates can confidently select the "No error" option. The key skill is to analyse each part systematically and only mark an error when you can clearly explain what is wrong and how to fix it.

Final Answer:
The sentence is grammatically correct in all its parts, so the correct choice is No error (D).