Which of the Following Is an Example of a Zero-Sum

Multiple Choice

Which of the following is an example of a zero-sum game?

A) Jill decides to buy a television set from Jack for $500.
B) Angela buys a jacket worth $30 from the apparel store near her apartment.
C) Rachel decides to buy Sarah's couch and is willing to pay whatever price Sarah might ask for it.
D) Joanna buys a camera at a Thanksgiving sale and gets a tripod free.