QUIZ 2
   (Z)

   |*|                 (A)        (B)         (C)
  /   \
 /     \ 
2      |+|           2*15+10   2*(15+10)   (2*15)+10
      /   \   
     /     \
    15     10

(Z)  -->  (A) | (B) | (C) ?

(Z)  -->