[单选题]
What happens to the t,m;d )cq;5 bccrd( gsgotmv)h +e 4y-ifxal relativistic energy of a speedy proton when its relativistici-)+vmhf 4x ey mass doubles?
A. It doubles.
B. It more than doubles.
C. It less than doubles.
D. It must increase, but it is impossible to say by how much.
