A particle of mass $100 \mathrm{~g}$ is thrown vertically upwards with a speed of $5 \mathrm{~m} / \mathrm{s}$. The work done by the force of gravity during the time the particle goes up is [2006]
(A) $-0.5 \mathrm{~J}$
(B) $-1.25 \mathrm{~J}$
(C) $1.25 \mathrm{~J}$
(D) $0.5 \mathrm{~J}$