Question

Which describes pumice and obsidian?

A.
Pumice is a coarse-grained extrusive igneous rock, while obsidian is a fine-grained intrusive igneous rock.

B.
Pumice is a fine-grained intrusive igneous rock, while obsidian is a coarse-grained extrusive igneous rock.

C.
Both pumice and obsidian are coarse-grained intrusive igneous rocks.

D.
Both pumice and obsidian are fine-grained extrusive igneous rocks.