If (m-8) is a factor of m^2-sm-24, then s=  Choose the correct answer:
A) 3 B) 5 C) 6 D) 11 E) 16

Rationale: "( m - 8 ) ( m - a ) = m ^ 2 - sm - 24 a = - 3 s = 8 + a = 5 = d = b"
Answer: B