The correct answer is option 3 - sandstone. Quartzite is a metamorphic rock that forms when sandstone is exposed to high levels of heat and pressure over time. It undergoes a process of metamorphism, which means that it undergoes physical and chemical changes due to these extreme conditions.

Option 1 - limestone: Limestone is a sedimentary rock formed from the accumulation of shells, coral, and other organic remains. While limestone can undergo metamorphism and turn into marble, it is not the precursor for quartzite.

Option 2 - plutonic rock: Plutonic rocks, such as granite, are formed by the cooling and solidification of magma deep within the Earth`s crust. While they can be involved in the formation of some metamorphic rocks, they are not directly related to the formation of quartzite.

Option 4 - shale: Shale is a fine-grained sedimentary rock composed mostly of clay minerals. It can undergo metamorphism and turn into slate or phyllite, but it is not the parent rock for quartzite.

In summary, quartzite is metamorphosed from sandstone through the process of intense heat and pressure, resulting in a rock with a high content of quartz grains.