Topic: Subject Verb Agreement,

Best Answer Explained in Below-:

The correct answer to the sentence "These grapes --- sour." is D) "taste." This choice maintains subject-verb agreement and fits grammatically and contextually within the sentence.

Firstly, let's analyze the subject of the sentence. "These grapes" is a plural noun phrase, indicating that we are talking about more than one grape. In English, the correct verb form must agree in number with the subject. The verb "taste" in its base form can be used with plural subjects in the simple present tense, making "They taste sour" an appropriate and accurate construction.

Option A, "tasting," would imply an ongoing action but does not appropriately complete the statement. Option B, "are tasting," uses the present continuous tense, which would suggest a temporary action rather than a permanent characteristic. Option C, "tastes," is singular and only applies to a singular subject, which does not correspond with the plural subject "grapes."

In summary, "taste" effectively communicates that the grapes possess the quality of being sour, making it the correct choice to complete the sentence accurately.