What is the sum of all coefficients when the following equation is balanced using the smallest possible whole numbers?

__ ${{\text{C}}_{\text{2}}}{{\text{H}}_{\text{2}}} +$ __ ${{\text{O}}_{\text{2}}} \to$ __ ${\text{C}}{{\text{O}}_{\text{2}}} +$ __ ${{\text{H}}_{\text{2}}}{\text{O}}$

A.     5

B.     7

C.     11

D.     13

D