HKD1710 wrote:

According to a study of city parks issued by the Trust for Public Land, New York City has 3.5 times as many parks per acre than the national average.

(A) has 3.5 times as many parks per acre than

(B) has 3.5 times as many parks per acre as

(C) has 3.5 times more parks per acre as

(D) have 3.5 times as many parks per acre as

(E) has 3.5 times as many parks per acre, more than

Will go with B

D is out for subject-verb number error

A and E are out for the 'than' at the end

With option C, the '3.5 times' and 'more parks.. as..' are redundant