Which transformation requires a complete meltdown of the rock into magma? a. igneous rock to sedimentary rock b. sedimentary rock to metamorphic rock c. metamorphic rock to sedimentary rock d. sedimentary rock to igneous rock e. igneous rock to metamorphic rock

The answer should be " E ", because the igneous rock will melt down creating magma then into metamorphic rock.

D. sedimentary rock to igneous rock

Explanation:

The compression of sediments (dust, dirt, sand) form the sedimentary rocks. The sediments can be formed from the erosion of metamorphic rocks or igneous rocks. This allows us to discard options  A and C.

Metamorphic rocks are partially melted rocks. The melted rocks could be sedimentary rock, igneous rock or an older metamorphic rock. We can discard options B and E.

The complete melting of sedimentary rocks or metamorphic rocks forms the igneous rock. If the meeting isn't complete the result will be a metamorphic rock. In this case, the complete melting is a requirement. The correct option is D.