Which of the following is a true statement about the self-interest assumption?
a.
self-interest players always maximize money.
b.
self-interest players will never perform an act of charity.
c.
self-interest players may sacrifice to punish others.
d.
self-interest implies that players are selfish.

d

Step-by-step explanation:

Self-interest assumption means that an action taken by a person can be termed as self interest if he or she has any basis or reason behind taking such action.  The individual always looks for profit and self benefit.Hence they can be treated as selfish.

So, if a person sacrifices his or her own interest so that others can be punished then such act can be termed as self-interest as person concerned is taking such action with a reason behind such act.

Hence, the correct answer is the option (d).