Explanation:

Two patterns are broadly observed.

One, rainfall reduces from coastal to interior areas.

Second, as mentioned in the question.

Any moisture-laden winds from ocean will first hit the coastal areas and then interior areas. Moisture would go on reducing as the wind advance further in. Poles receive lesser solar insolation, have lesser evaporation and rainfall.

Reverse is true for equator. So, A is correct. Jet Streams do not play a significant role here and so Option D can be neglected.