For a gasous reaction, `2A+B hArr 2C`, the partial pressures of A,B and C at equilibrium are 0.3 atm, 0.4 atm and 0.6 atm respectively. The value of `K_P` for the reaction would be :
A. `10 "atm"^(-1)`
B. `1/10 "atm"^(-1)`
C. `0.2 "atm"^(-1)`
D. `5 "atm"^(-1)`