In an `LR`-circuit, the inductive reactance is equal to the resistance `R` of the circuit. An e.m.f `E=E_(0)cos (omegat)` applied to the circuit. The power consumed in the circuit is
A. `E_(0)^(2)//R`
B. `E_(0)^(2)//2R`
C. `E_(0)^(2)//4R`
D. `E_(0)^(2)//8R`