Two Identical 5000-Kg Bulldozers Roll Toward Each Other on a Level

Two identical 5000-kg bulldozers roll toward each other on a level road without friction (one at 1 m/s, the other at 2 m/s) Just before they collide, one has a kinetic energy of 2500 J and the other
10,000 J. t this instant their total kinetic energy is

A) 7500 J.
B) 10,000 J.
C) 12,500 J.
D) 1250 J.
E) 2500 J.