A Sledge (Including Load)weighs 5000 N

Multiple Choice

A sledge (including load) weighs 5000 N.It is pulled on level snow by a dog team exerting a horizontal force on it.The coefficient of kinetic friction between sledge and snow is 0.05.How much work is done by the dog team pulling the sledge 1000 m at constant speed?

A) 0 J
B) 2.5 * 10⁵ J
C) 5.0 *10⁵ J
D) 2.5*10⁶ J
E) 5.0*10⁶ J