Which of the following sentences uses the correct subject-verb agreement.
a. at the party there were no one i knew.
b. there was many problems with the construction of the house.
c. one important aspect of the book is it detailed descriptions.

C. One important aspect of the book is it detailed descriptions.

Explanation:

A. At the party there were no one I knew.

Wrong. The subject is in the first person singular form. Thus, the use of the verb "were" should be changed to "was".

B. There was many problems with the construction of the house.

Wrong. The use of the verb "was" is wrong. The subject is plural, thus the verb will also have to be in the plural form.

C. One important aspect of the book is it detailed descriptions.

Correct. The verb "is" agrees with the subject "it".

i used to know but i learned it a long time ago sorry

explanation:

2nd person

hope this !