The desire for praise is the desire to obtain, as a sign that one is good, the favorable opinions of others. But because people merit praise only for those actions motivated by a desire to help others, it follows that one who aids others primarily out of a desire for praise does not deserve praise for that aid. Which one of the following, if assumed, enables the conclusion of the argument to be properly drawn? ["One deserves praise for advancing one's own interests only if one also advances the interests of others.", 'People who are indifferent to the welfare of others do not deserve praise.', 'An action that is motivated by a desire for the favorable opinion of others cannot also be motivated by a desire to help others.', 'No action is worthy of praise if it is motivated solely by a desire for praise.']