An aeroplane is moving on a circular path with a speed of $250 \;kmhr^{-1}$ The change in its velocity in half revolution is

Question

$\begin{array}{1 1}(A)\;0 \\(B)\;250\;km\;hr^{-1} \\(C)\;500\;km\;hr^{-1}\\(D)\;250 \sqrt 2 \;km\;hr^{-1} \end{array}$