C is correct.
Peter's jacket cost .........Jack's.
a. twice more than
b. two times more as
c. twice as much as
d. twice more as
Here above is the test I found in Digest (Trudy Aronson)
I didn't find it out why 'c' is written as the answer. I guessed first 'a' must be the answer.
Could you please help? Thanks.