For the reaction `A_(2)(g) + 2B_(2)hArr2C_(2)(g)` the partial pressure of `A_(2)` and `B_(2)` at equilibrium are `0.80` atm and `0.40` atm respectively.The pressure of the system is `2.80` atm. The equilibrium constant `K_(p)` will be
A. (A) `20`
B. (B) `5.0`
C. (C) `0.02`
D. (D) `0.02`