What rocks forms when limestone undergoes metamorphism?

Marble is the correct answer.

Explanation:

Marble rocks forms when limestone undergoes metamorphism.

Marble rock is formed from the limestones,when the limestone is influenced by heat and tremendous pressure it transforms in marble through a method called metamorphism.

During the metamorphism, limestone gets recrystallizes and result in the formation of interlocking carbonate mineral crystals that form the marble.

answer at the divergent plate boundary in the middle of the ocean;