Quartzite is metamorphosed from which one of the following rocks?

Quartzite is a hard, non-foliated metamorphic rock formed by the metamorphism of sandstone, which is composed predominantly of quartz grains. Under heat and pressure, the quartz grains recrystallise and fuse together. By contrast, limestone metamorphoses to marble, shale metamorphoses to slate (and subsequently phyllite/schist), and pegmatite is itself an igneous rock. Hence sandstone is the protolith of quartzite.