Which of the following is an example of a metamorphic rock?

Marble is an example of a metamorphic rock because it forms from the metamorphism of limestone under high pressure and temperature conditions. The process involves recrystallization, where the original minerals in limestone change structures, resulting in new minerals that make up marble. This transformation alters the texture and appearance, producing a denser, often more aesthetically appealing stone that is commonly used in sculpture and architecture.

The other types of rocks mentioned are classified differently: the basalt is an igneous rock resulting from volcanic activity, limestone is a sedimentary rock primarily made of calcium carbonate which forms from the accumulation of marine organism remains, and pumice is also an igneous rock, characterized by its light weight and porous texture due to rapid cooling of lava. Each of these has distinct formation processes, which differentiates them from metamorphic rocks like marble.