In this English grammar error spotting question on subject verb agreement, identify the incorrect part of the sentence: "Her parents has not permitted her to marry Sunil."

Introduction / Context:
This question focuses on subject verb agreement in the present perfect tense. The sentence is "Her parents has not permitted her to marry Sunil." The candidate must check whether the auxiliary verb agrees with the subject number. Subject verb agreement is a core grammar topic and appears frequently in competitive examinations because it affects the clarity and correctness of almost every sentence.

Given Data / Assumptions:

• The sentence describes a decision made by her parents regarding marriage.
• Segment (a) is "Her parents".
• Segment (b) is "has not permitted her".
• Segment (c) is "to marry Sunil.".
• Segment (d) is "No error".
• We assume "parents" is a plural noun here, referring to both father and mother.

Concept / Approach:
In English, plural subjects require plural verb forms. "Parents" is plural, so the correct auxiliary verb in the present perfect tense is "have", not "has". The correct phrase should be "have not permitted". The rest of the verb phrase "permitted her to marry Sunil" is acceptable. Therefore, the only problem is the mismatch between the plural subject "parents" and the singular auxiliary "has".

Step-by-Step Solution:
Step 1: Identify the subject of the sentence, "Her parents", which clearly refers to more than one person. Step 2: Recall that plural subjects take "have" rather than "has" in the present perfect tense. Step 3: Look at segment (b) "has not permitted her" and spot that it uses "has" instead of "have". Step 4: Replace "has" with "have" to form the correct verb phrase "have not permitted her". Step 5: Check segment (c) "to marry Sunil." and confirm that it completes the idea logically and grammatically. Step 6: Conclude that the error lies only in segment (b).

Verification / Alternative check:
Compare with similar sentences: "Her parents have decided to move", "My friends have not visited me", and "The students have completed their work." In each case, the plural subject takes "have" in the present perfect form. If we used "has" with these plural subjects, the sentences would sound wrong to an experienced speaker. Applying the same logic here, "Her parents have not permitted her to marry Sunil" is the only correct version, confirming that segment (b) is faulty.

Why Other Options Are Wrong:
Option (a) "Her parents" is a correct plural subject phrase. Option (c) "to marry Sunil." is a correct infinitive phrase expressing the action not permitted. Option (d) "No error" cannot be correct, because the verb agreement in segment (b) is clearly wrong.

Common Pitfalls:
Learners sometimes look only at the nearest noun or think of "parents" as a single unit, leading them to use "has" instead of "have". To avoid this, always identify whether the subject is singular or plural in meaning. Words ending in "s" are often plural, and subjects like "parents", "children", and "friends" definitely require plural verbs. Regularly practising agreement with common plural subjects helps make the correct forms automatic.

Final Answer:
The incorrect part is option (b) "has not permitted her". It should read "have not permitted her". Therefore, the correct answer is "has not permitted her".