In Western Canada,the Coast Receives Far More Rainfall Than the Eastern

In western Canada,the coast receives far more rainfall than the eastern portion of the area.What accounts for this stark contrast?

A) The coast experiences a great deal of frontal lifting,while the eastern portion is under a high pressure cell.
B) The coast experiences orographic precipitation,while the easternmost portion is in the rain shadow.
C) The coast has much more moderate temperatures due to the maritime effect and,therefore,experiences convectional uplift,while the eastern portion is governed by continentality.
D) The coast is under the ITCZ during the summer and experiences convergent uplift,while the eastern portion is under the Azores High and experiences subsiding air.