If the magnets are brought close together, they will

opposites attract

and if they are the same they will pull away from eachother

Opposite poles of a magnet attract each other, whereas like poles repel each other. When lined up with a south-seeking pole, a north-seeking pole would draw closer to that end of the magnet. However, when lined up with another north-seeking pole, the two magnets would push away from each other because their forces are not compatible

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.

reserve is the answer