Steve Currently Subscribes to Two Magazines and Is Trying to Decide

Multiple Choice

Steve currently subscribes to two magazines and is trying to decide whether to subscribe to a third.Which of the following would best determine his decision if he is acting rationally?  

A)  the total cost of the magazines compared to the total satisfaction Steve would receive 
B)  the total amount of satisfaction Steve would receive from the magazines 
C)  the cost of the third magazine, including the time it takes Steve to read it 
D)  the cost of the third magazine compared to the additional enjoyment Steve would receive from it