I was looking at the practice test and there is problem 2 stating

"Two springs, S1 and S2 have negligible masses and the spring constant of S1 is 1/3 that of S2. When a block is hung from the spring as shown above and the spring comes to equilibrium again the ratio of the work done in stretching S1 to the work done in stretching S2 is

A 1/9

B 1/3

C 1

D 3

E 9"

The answer given by ets is D but I don't really agree with this: I mean, it should be easier (so less work is needed) to stretch the spring with the smaller spring constant so I would say the answer should be 1/3. At least supposing the springs are ideal and obey to the 1/2kX^2 rule for most of the possible dx's

please help!