Concept:The phrase "it's about time" requires a past tense verb to refer to a present or future wish.
Explanation:The sentence suggests that the brother is not giving enough attention to English at the moment.
In English, after expressions like "it's about time" or "it's high time", we use the simple past tense.
This past tense acts as a subjunctive and describes something that should happen now or soon.
The verb "pay" changes to "paid" in its simple past and past participle forms.
Option A, "pays", and Option B, "is paying", are present tense forms and are not suitable here.
Option D, "had paid", is past perfect and is not used with this structure.
Thus, the correct verb is "paid", meaning to give attention to someone or something.
Answer:C. paid