Students of Microeconomic Principles Often Say They Are Going to Study

Students of microeconomic principles often say they are going to study "tonight," because the only way to pass the exam is to study some every night. When "tonight" comes, some students choose to do something else. Come exam day, these students do not do well on their exam. This observation is an example of how people are

A) inconsistent over time.
B) consistent over time.
C) mainly interested in fairness.
D) rational.