The correct answer is option 1: Sedimentary rock. Dolomite is a type of sedimentary rock that is composed mainly of the mineral dolomite, which is a calcium magnesium carbonate. It is formed through the chemical precipitation of the mineral from water that is rich in magnesium and calcium ions. Dolomite commonly forms in marine environments, where it can be found in the form of limestone or dolostone.

Option 2: Plutonic rock is incorrect because plutonic rocks are igneous rocks that cool slowly beneath the Earth`s surface and are typically composed of minerals such as granite or gabbro.

Option 3: Igneous rock is incorrect because while dolomite can form as a result of the transformation of limestone, it is not classified as an igneous rock, which forms from cooling and solidification of molten magma or lava.

Option 4: Metamorphic rock is incorrect because dolomite is not formed as a result of the metamorphic process, which involves the alteration of existing rocks through heat and pressure.