The direction in which force $(F=13 \mathrm{~N})$ is applied is at
(A) $90^{\circ}$ with the direction of motion of the train.
(B) $\cos ^{-1} \frac{5}{13}$ with the direction of motion of the train.
(C) $\cos ^{-1} \frac{5}{12}$ with the direction of motion of the train.
(D) $\cos ^{-1} \frac{12}{13}$ with the direction of motion of the train.