$6.($Achieve HW $8,$ #$3)$ A tennis player smashes a ball of mass $$ horizontally at a vertical wall. The ball

rebounds at the same speed $$ with which it struck the wall. Has the momentum of the ball changed, and if so$,$

by how much?

A$.2$

B$.4$

C$.$

D$.0$

E$.0\mathrm{.}5$