Which sentence displays correct subject verb agreement

1. The books at the library is very helpful

2. The cattle in the feild is huge!

3.My collection of stamps is extensive

4. The island visited by the trvelers are warm

3. My collection of stamps is extensive.

The sentence that displays correct subject-verb agreement is:

3. My collection of stamps is extensive.

The sentence that displays correct subject-verb agreement is:

3. My collection of stamps is extensive.

Explanation:
Subject-verb agreement means that the subject and the verb in a sentence must agree in number. In sentence 1, the subject "books" is plural, but the verb "is" is singular, so there is a disagreement. In sentence 2, the subject "cattle" is plural, but the verb "is" is singular, so there is also a disagreement. In sentence 4, the subject "island" is singular, but the verb "are" is plural, so there is a disagreement.

In contrast, sentence 3 has a singular subject "collection" and a singular verb "is," so there is agreement between the subject and verb.