A particle of mass $5 \mathrm{~kg}$ moving in the $X-Y$ plane has its potential energy given by $U=(-7 x+24 y)$ Joule. The particle is initially at origin and has velocity $\vec{u}=(14.4 \hat{i}+4.2 \hat{j}) \mathrm{m} / \mathrm{s}$
(A) The particle has speed $25 \mathrm{~m} / \mathrm{s}$ at $t=4 \mathrm{~s}$.
(B) The particle has an acceleration $5 \mathrm{~m} / \mathrm{s}^{2}$.
(C) The acceleration of particle is normal at its initial velocity.
(D) None of these.