The non-zero verctors $\overrightarrow{a}$ , $\overrightarrow{b}$ and $\overrightarrow{c}$ are related by $\overrightarrow{a} =8\overrightarrow{b} and \overrightarrow{c} = -7 \overrightarrow{b}$ .Then the angle between $\overrightarrow{a}$ and $\overrightarrow{c}$ is

Question

( A ) 0
( B ) $\frac{\pi}{4}$
( C ) $\pi$
( D ) $\frac{\pi}{2}$