his father （ ）to work by car ,but now he goes to work on foo

C.
1）used to do 过去常常做
I used to read newspapers last year.
2）be used to doing sth=
be accustomed to sth/doing sth
习惯于做某事
I am used to going to company by bus.
我习惯于乘车去公司.
I am accustomed to the weather here.
我已经适应了这里的天气了.
3）be used to do 被用来做（表示被动）
Wood is used to make paper.
木头被用来造纸.

B.used to du过去常常
be used to doing习惯于

B
be used to doing是习惯做某事
used to do sth 过去常常（意思是现在已经没有了）