Limestone changes into ________ due to metamorphism.

Answer: Option A

Limestone changes into Marble due to metamorphism. Marble is a metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism. It is composed primarily of the mineral calcite (CaCO₃) and usually contains other minerals, such as clay minerals, micas, quartz, pyrite, iron oxides, and graphite.