For a white body, the reflective power is -

The correct option is D $1.0$
Reflective power is defined as,

$r=\frac{\text{Energy reflected}}{\text{Energy incident}}$

A white body is one with a "rough surface that reflects all incident rays completely and uniformly in all directions".

$\therefore \text{Energy reflected}=\text{Energy incident}$

$\Rightarrow r=1$

Hence, option $\left(D\right)$ is the correct answer.