Answer
$C$ can be less or equal to $A+B$ but can not be greater than $A+B$
Work Step by Step
we have
$\vec C = \vec A + \vec B$
If the angle between $ \vec A $ and $ \vec B$ is equal to $0$ or $2\pi$ then
$C= A+ B$
For any other angle ( between $ \vec A$ & $ \vec B$ ), $C$ is always less than $A+B.$
