In the following sentence error question, identify the part that contains a grammatical error or choose No Error: Why you (A) / copying your homework (B) / from someone else? (C) / No Error (D).

Introduction / Context:
Error spotting questions check a learner ability to notice mistakes in subject verb agreement, tense, word order, and common usage. The given sentence is a question asked in the present continuous tense about an action that is happening now. In English, questions in this tense require the auxiliary verb before the subject. The incorrect arrangement in one part of the sentence must be identified.

Given Data / Assumptions:

• Sentence parts: Why you (A) / copying your homework (B) / from someone else? (C) / No Error (D).• The speaker is clearly asking a present time question about copying homework.• The correct form in standard English is Why are you copying your homework from someone else.• We assume no change in meaning, only correction of structure.

Concept / Approach:
In present continuous questions, the pattern is auxiliary verb plus subject plus main verb with ing. For the subject you, the correct auxiliary is are. Therefore, the sentence should begin Why are you copying, not Why you copying. The error lies in the first part, where the auxiliary is missing. The remaining parts copying your homework and from someone else are correctly formed phrases attached to the verb copying.

Step-by-Step Solution:
Step 1: Identify the intended tense and form. The phrase copying your homework shows present continuous.Step 2: Recall that the question form in this tense is formed with are for the subject you.Step 3: Examine part A Why you. It lacks the necessary auxiliary are and therefore is ungrammatical in a question.Step 4: Examine part B copying your homework. This is a correct present participle phrase following the auxiliary that should be added.Step 5: Look at part C from someone else. This prepositional phrase is also correct and clearly expresses the source of the copied work.Step 6: Conclude that only part A contains an error, and the corrected form must be Why are you.

Verification / Alternative check:
Read the corrected sentence aloud: Why are you copying your homework from someone else. It sounds natural and follows standard English question structure. If we leave part A unchanged and instead change other parts, the sentence would still feel incorrect, because the central issue is the missing auxiliary in the question opening. Therefore, part A is the only problematic segment and must be marked as containing the error.

Why Other Options Are Wrong:
Part B copying your homework correctly uses the ing form after the auxiliary are and directs the verb towards the object homework. Part C from someone else correctly uses from to indicate the source. Part D No Error would be selected only if the sentence were fully correct, which it is not. Hence B, C, and D cannot be the right choices for the error location.

Common Pitfalls:
Students sometimes overlook auxiliary verbs in question formation because spoken language in some regions may omit them. Others may quickly assume that long phrases like from someone else contain the mistake. A disciplined approach is to first identify the tense and structure, then check whether the pattern is properly followed for the subject and main verb. This makes it easier to detect that Why you must be changed to Why are you.

Final Answer:
The error is in part A, which should be Why are you instead of Why you.