(A) The student gave four practice exams for the GMAT and achieved an average score of 650.Correct choice.
Meaning is clear. No SVA, tense, pronoun, modifier,parallelism, idioms, meaning & other error.
(B) The student
took four practice exams for the GMAT and achieved an average score of 650.
It means the student was the invigilator of the GMAT exam & scored 650! Totally skewed & illogical meaning.
(C) The student finished four practice exams to
their end for the GMAT and achieved an average score of 650.
to their end for the GMAT:- pronoun ambiguity. ‘their’ should logically refer ‘singular’ antecedent ‘The student’, but grammatically incorrectly refers here to GMAT exams.
(D) Four practice exams
were taken by the student for the GMAT and
achieved an average score of 650.
Passive voice is not preferred if active voice is there.
Parallelism error:- logically achieved should refer student. But grammatically ‘student’ is within prepositional phrase, so could not be act as subject.
Exams were taken:- same ‘give & take’ error as B
(E) Four practice exams
were completed by the student for the GMAT and
achieved an average score of 650.
Parallelism error:- same as D
Passive voice- same as D