Final answer:
The decision maker will have to make a decision under conditions of uncertainty when their information is not complete.
Step-by-step explanation:
The condition described in the question, where the decision maker's information is not complete, is known as uncertainty.
Uncertainty occurs when there is imperfect information and the decision maker is unsure about the outcome or the characteristics of the options available.
Unlike certainty, where all information is known, uncertainty introduces an element of risk and makes it more challenging for the decision maker to make an informed choice.