if a@b = a * b^(1/2) then 4@9 = ?
self made  Choose the most appropriate option:  A) 2  B) 12  C) 3  D) 8  E) 4

Rationale: 4 * ( 9 ) ^ 1 / 2 = 4 * 3 = 12 b is the answer
Answer: B