Question

which type of ultrabasic rock sometimes contains diamonds?
granite
kimberlite
pegmatite
rhyolite

Explanation:

Kimberlite is an ultrabasic igneous rock that is known to sometimes contain diamonds. Granite is a felsic intrusive igneous rock, pegmatite is a coarse - grained igneous rock often associated with certain minerals but not typically diamonds in the context of ultrabasic rocks, and rhyolite is a felsic extrusive igneous rock.

Answer:

kimberlite