English Grammar — Spot the error (choose the incorrect part; select 'No error' if the sentence is correct). Sentence parts: A) The new facts he B) has discovered and the new C) arguments he has advanced D) has not changed my opinion. E) No error

Introduction / Context:
This question examines subject–verb agreement across a compound subject joined by “and.” The error lies in choosing the correct auxiliary form “have/has” to match a plural subject.

Given Data / Assumptions:

• Compound subject: “the new facts … and the new arguments …”
• Predicate verb phrase uses “has not changed.”
• Plural subject requires plural auxiliary “have.”

Concept / Approach:
With coordinated nouns linked by “and,” the subject is plural, so the verb must also be plural. Therefore, “have not changed” is correct, not “has not changed.”

Step-by-Step Solution:

Verification / Alternative check:
Replace the subject with a singular to test: “The new set of facts and arguments has …” In the original, no collective “set” exists; the head is plural, confirming “have.”

Why Other Options Are Wrong:

• A, B, C: Each segment is grammatically well-formed.
• E: Not applicable because D contains the error.

Common Pitfalls:
Writers are misled by the proximity of a singular auxiliary in relative clauses or by the distance between subject and main verb. Always return to the true grammatical subject before choosing verb number.

Final Answer:
D) has not changed my opinion.