Final answer:
The western hemlock tree grows well in Washington's cool, moist, and shady forests due to its shade tolerance and suitability to coastal temperate rainforests. Therefore, the correct option is d) western hemlock
Step-by-step explanation:
The tree that grows well in Washington's cool, moist, and shady forests is the western hemlock (Tsuga heterophylla). Western hemlock is found in the Pacific northwest and is known for being extremely shade tolerant. It is a tall tree species that reaches substantial heights and is commonly found in coastal temperate rainforests.