If a - b = 3 and a^2 + b^2 = 35, find the value of ab.	Choose the most appropriate option:
A) 12
B) 13
C) 10
D) 18
E) 13

Rationale: "2 ab = ( a ^ 2 + b ^ 2 ) - ( a - b ) ^ 2 = 35 - 9 = 26 ab = 13 . answer is b ."
Answer: B