People have a tendency to judge stimuli relative to those previously experienced. For example, if a manʼs current income level increases, he feels an initial surge of pleasure. However, as he adjusts to that income level, he comes to consider the new level normal. He then requires something better to feel another surge of happiness. This is known as

the adaptation-level phenomenon        

Explanation:

This situation is known as the adaptation-level phenomenon. The tendency for individuals to rapidly adjust/adapt to a new stimulus/situation until it becomes normal is known as the adaptation-level phenomenon. For example, when an individual an individual buys a new car, he/she has a feeling of euphoria, however, as he/she continues to use the car, that feeling normalizes, like his/her emotion of happiness recalibrates.

Options A, B, and D, follows.

Explanation:

To gain territory in the Pacific, to move closer to Japan, to weaken Japanese forces, are the right options.

Island Hopping was a military strategy in the Pacific War exercised the Allied powers against the Axis powers (particularly, Japan)  throughout the Second World War. The strategy involved the taking over of an island and building an army camp there. The camp was in turn managed as a launching spot for the invasion and takeover of another island. In short, the Island Hopping strategy focused on strengthening the power of the Allied powers by gaining territory in the Pacific, moving closer to Japan and weakening the Japanese force.