Let $f$ be differentiable for all $x$. If $f(1) = -2$ and $f'(x) \geq 2$ for $x \in [1,6]$, then :

Question

( A ) $f(6) \geq 8$
( B ) $f(6) < 5$
( C ) $f(6)=5$
( D ) $f(6)< 8$