Answer:
the awnser is c
Explanation:
A- 100:1 would mean it is a 10000% markup
B- 1:100 lower than b so eliminate
C- 2:1 So a is double the amount of b so it's 100%
D- 1:2 B is 100% of a so it's flipped, not what question is asking for
So process of elimination shows that C is the correct awnser