Final answer:
The underlying assumption of the administrative model of decision making is that people make decisions influenced by unconscious mental habits and cognitive models, which can sometimes result in irrational or suboptimal choices.
Step-by-step explanation:
Fundamental Assumption of the Administrative Model of Decision Making
The question concerns the administrative model of decision making, which essentially assumes that human beings do not always make decisions rationally or logically. This is in direct contrast to classical economic models which propose that people are fully rational actors who seek to maximize their utility in a consistent and informed manner. In reality, however, decisions are often influenced by unconscious mental habits and models. This can lead to decisions that seem inconsistent, irrational, or even contrary to one's self-interest.
To address the question presented, the fundamental underlying assumption of the administrative model of decision making is that:
c. People make decisions based on unconscious mental habits and models.
This option reflects the concept that humans frequently operate from a position that involves automatic processing influenced by cognitive biases and limitations in information processing capabilities.