Which region historically relied most on a large population for manufacturing industries?
A.
Silicon Valley
B.
Frostbelt states
C.
Rustbelt states
D.
Sunbelt states

None of them. they are likely to occur on any plate boundary

Your answer is d. silli hope this ! : ) i left an explanation down below if you need it: a sill forms when hot magma squeezes between layers of rock to form a hardened sheet of rock. a sill is basically a tabular sheet intrusion between old layers of sedimentary rock, volcanic beds, or in the direction of foliation inherent in metamorphic rock. the word sill means a concordant intrusive sheet.