Answer: Option (d) is the correct answer.
Step-by-step explanation:
Work is defined as the force applied in order to move an object from a certain distance.
Mathematically, W = F × d
where, w = work
F = force
d = distance
Thus, when Lester lifts the sack to his chest from the floor then he is doing work as he is applying force on the sack in order to move it over his chest.