Answer: A. soon be worried again about his finances.
Step-by-step explanation:
Adaptation-Level Phenomenon simply means that people adapt to a new situation quickly and once the new situation becomes normal, they strive for a new one experience.
With regards to the situation, we are informed that Mike Pensive has been short of money and worried about his job security and that he later got an increase in salary. Research on long-term happiness suggests that he will soon be worried again about his finances.
This is because the new situation would have become normal to him and he'll be wanting more as time increases.