[单选题]
What happens to the kinetto5+n3 c5c a :5s0jkveork0 ntnj+fm2y g 8r -cs)b-kkeji)-sic energy of a speedy proton when its relativistic mass +k r-s-)-jke2 jy )b8cmifgnsdoubles?
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.
