The rate of the first order `Ararr` Products, is `7.5xx0^(-4) "mol" L^(-1)s^(-1)` , when the concentration of A is 0.2 mol `L^(-1)` . The rate constant of the reaction is :
A. `2.5xx10^(-5)s^(-1)`
B. `8.0xx10^(-4)s^(-1)`
C. `6.0xx10^(-4)s^(-1)`
D. `3.75xx10^(-3)s^(-1)`