Answer:
D. one optimal solution to a problem.
Step-by-step explanation:
The Rational Choice Theory is proposed by Adam Smith in the late eighteenth century. The Rational choice theory is used in number of fields such as philosophy, economics, and psychology.
According to this theory, people tend to make choices that includes self-interest and will benefit them in the long run. The first assumption of rational choice theory is that consumers seek personal preference and one optimal solution to a problem and make decision based on this preferences.
Therefore, the correct option is D.