Which most motivated european nations to take control of areas in asia and africa in the 1800's

a. the possibility of discovering lost cities and civilizations and unearthing fossils

b. the need for raw material and fuel for new indisteries, and a place to sell finished goods

c. the need for a place to send exess population as the land became overcrowded

d. the upper class desire to buy silks, spices, and other goods not produced in europe