Which is an example of a person selling their labor to earn an income? A.
Claude works as a cashier for a local store.
B.
Erich attends a local public school.
C.
Hans volunteers at a homeless shelter.
D.
Ivan walks the dogs in his neighborhood.

The correct answer is:  

Talking about the secret garden is painful for Ben.

In The Secret Garden (1911), a novel by Frances Hodgson Burnett,  the gardener Ben Weatherstaff finds it painful to talk about the late Mrs. Craven, who used to spend hours in the secluded garden growing roses. Mrs. Craven had died after a mishap in the garden, so Mr. Craven locked the garden and hid the key.