If Wire Hair (W)is Dominant to Smooth Hair (W),and You

Multiple Choice

If wire hair (W) is dominant to smooth hair (w) ,and you find a wire-haired puppy,which type of puppy would you use in a testcross to determine its genotype?  

A) Heterozygous wire-haired puppy
B) Homozygous wire-haired puppy
C) Heterozygous smooth-haired puppy
D) Any smooth-haired puppy
E) True-breeding wire-haired puppy