If the expected number of valid shifts is small and modulus is larger than the length of pattern what is the matching time of Rabin Karp Algorithm?

If the expected number of valid shifts is small and modulus is larger

1.	If the expected number of valid shifts is small and modulus is larger than the length of pattern what is the matching time of Rabin Karp Algorithm?
A.	Theta(m)
B.	Big-Oh(n+m)
C.	Theta(n-m)
D.	Big-Oh(n)
Answer» C. Theta(n-m)