The single-family house constructed by the Yana, a Native American people who lived in what is now northern California, was conical in shape, its frameowrk of poles overlaid with slabs of bark, either cedar or pine, and banked with dirt to a heigh of three to four feet.

a.
b. banked with dirt as high as that of
c. banked them with dirt to a height of
d. was banked with dirt as high as
e. was banked with dirty as high as that of


Please give me your comments on my thought process.

A. to a height of is awkward.
B. as high as that of three to four feet is awkward
c. banked them with dirt to a height of.. not parallel. banked them is a verb phrase. conical in shape is not.
d. was banked with dirt as high as --- The house WAS conical in shape and WAS banked with dirt . parallel. correct.
e. was banked with dirt as high as that of -- wordy and awkward.