A child with terrible taste in candy likes to mix his MnMs and Skittles into the same bag. His bag of mixed candy contains:
9 blue MnMs
21 red MnMs
20 yellow MnMs
0 blue Skittles
16 red Skittles

How many red candies are in the bag?
a) 37
b) 37 MnMs and 16 Skittles
c) 21
d) 16