Quote:
One reason that the student was ahead of her classmates
was
because of having taken summer school through the local college.
(A) because of having taken summer school
(B) her having taken summer school
(C) that she had taken summer school(D) because she took summer school
(E) she had taken summer schoolE is better. Parallelism is not an issue here. Looking at both -
C) One reason that the student was ahead of her classmates was that she had taken summer school through the local college
E) One reason that the student was ahead of her classmates was she had taken summer school through the local college
C) is of the form - One reason that X was that Y
E) is the form - One reason that X was Y
E is more concise.
As far as narrowing down to C & E goes - The main thing to notice here is that fact that this sentence involves two actions taking place in the past, one before the other.
student was ahead ..... and ........... having taken summer school.
which one took place first ? summer school. Therefore, summer school happened first and as a result the student was ahead.
I believe this is the case of PAST PERFECT TENSE. The earlier action uses past perfect tense (had + past participle) and the latter action uses simple past tense. As a result, the earlier action in this case,
had taken summer school is the HAD + past particle TAKEN.
However, I am slightly confused because "the student was ahead of her classmates" is not in simple past tense.