Sentence Correction

A group of students who have begun to clean up Frederich Olmsted's Morningside Park in the New York City believes that the park needs not to be redesigned but to be returned to its former condition.

A. believes that the park needs not to be redesigned but to
B. believe that the park needs to not be redesigned but to
C. believes that the park needs to be redesigned but could
D. believe that the park needs to be not redesigned but to
E. believe that the park needs not to be redesigned but that it

1.

SV Agreement. --> Eliminate everything except A and C

Group = Subject = singular

2.

Parallelism

X but Y

not to be XY but to be XZ

C is not parallel.

Thus a is the answer.

BastiG wrote:
Parallelism

X but Y

Just want to add that, the correct marker is,
not (only) X but (also/rather) Y