Minivans carry as many as seven passengers and, compared with most sport utility vehicles, cost less, get better gas mileage, allow passengers to get in and out more easily, and have a smoother ride.

A.    Minivans carry as many as seven passengers and, compared with most sport utility vehicles, cost less,

B.    Minivans, which carry as many as seven passengers, compared with most sport utility vehicles, they cost less,

C.    Minivans carry as many as seven passengers, in comparison with most sport utility vehicles, and have a lower cost, they

D.    Minivans, carrying as many as seven passengers, compared with most sport utility vehicles, cost less,

E.     Minivans, which carry as many as seven passengers, compared with most sport utility vehicles the cost is lower, and they

The answer is A, why not D? In A, the structure is " Minivans carry... and cost.., allow..., and have.... The first "and" is unecessary. In D, the structure is "Minivans,     , cost..., allow..., and have... ", the structure accords with parallelism.

Many thanks.