In a projectile motion, the acceleration in the x –direction(ax)is “0”. Why? A). Because the velocity in the y –direction is constant
B). Because the velocity in the x –direction is “0”
C). Because the velocity in the y –direction is “0”.
D).Because the velocity in the x –direction is constant

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

i think the answer is a, hope this : )