Would you mind explaining the solution. Already enough people have pounded on this.
1. The events A and B cannot be mutually exclusive.
P(A) + P(B) > 1
so, the minimum value of C cannot be 0.
the minimum C is 0.83 + 0.25 - 1 = 0.08
2. About the maximum, that will occur when B is a subset of A.
that is C = 0.25
you answer then is Range = 0.25 -0.08 =0.17