All of the following are examples of unpaid labor, except
a. cooking for one’s own family
b. cleaning the house of a wealthy family for small wages
c. taking care of one’s children or elderly family members
d. working in the family vegetable garden

The correct answer is the second (B).

Unpaid work is that type of work in which the person does not receive any amount of money in return. Normally, unpaid work is done at home, through household chores or in favor of relatives.

Working by cleaning up another family's house receiving too much or too little is a form of paid work. That is, paid work is all work in which there is a financial reward, regardless of the amount.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.