Two Masses Are Connected by a String Which Passes Over $4.00 \mathrm{~kg}$

Two masses are connected by a string which passes over a pulley with negligible mass and friction. One mass hangs vertically and one mass slides on a 30.0 degree incline. The inclined surface has a coefficient of kinetic friction of 0.200 . The vertically hanging mass is $4.00 \mathrm{~kg}$ and the mass on the incline is $6.00 \mathrm{~kg}$ . The magnitude of the acceleration of the $4.00 \mathrm{~kg}$ mass is (the initial velocity of the $6.00 \mathrm{~kg}$ mass is down the incline)

A) $2.98 \mathrm{~m} / \mathrm{s}^{2}$ .
B) $3.90 \mathrm{~m} / \mathrm{s}^{2}$ .
C) $5.84 \mathrm{~m} / \mathrm{s}^{2}$ .
D) $1.53 \mathrm{~m} / \mathrm{s}^{2}$ .
E) $7.16 \mathrm{~m} / \mathrm{s}^{2}$ .