The subject of the sentence begins with “Each of…,” which is always considered singular, regardless of the plural noun that follows.
Therefore, the verb must also be singular — “has” rather than “have.”
Option (A) is correct: “Each of the students has done well” maintains both correct subject-verb agreement and proper plural form “students.”
Option (B) incorrectly uses the singular “student” after “each of the,” which requires the plural “students.”
Option (C) uses the correct plural noun “students” but incorrectly pairs it with “have” instead of “has.”
Option (D) makes both errors — singular “student” after “each of the” and incorrect verb “have.”
Thus, (A) is the only grammatically correct sentence.