548 from 1000sc

[senthil]

548. On the Great Plains, nineteenth-century settlers used mud and grass to build their homes, doing it without timber and nails.
(A) settlers used mud and grass to build their homes, doing it without
(B) settlers used mud and grass to build their homes, did it without
(C) settlers used mud and grass to build their homes, making them while not having
(D) settlers used mud and grass to build their homes, making do without

I chose B because used , build were in past tense so I felt the dependent clause should be in past too

[tar.goyal]

I think A should be the answer.

C and D seem awkward and should be eliminated.

[senthil]

A is the answer but why ?
PLease explain'

Senthil