Arnold and Danny are two twin brothers that are celebrating their birthday. The product of their ages today is smaller by 11 from the product of their ages a year from today. What is their age today?	Pick:
A) 2 .	B) 4 .	C) 5 .	D) 7 .	E) 9 .

Rationale: "ad = ( a + 1 ) ( d + 1 ) - 11 0 = a + d - 10 a + d = 10 a = d ( as they are twin brothers ) a = d = 5 c is the answer"
Answer: C