(a) Igneous rock
(b) Metamorphic rock
(c) Sedimentary rock
(d) Calcareous rock
Ans :- (a) Igneous rock

Explanation:-
Igneous rock- It is also known as primary, unstratified or eruptive rocks are of volcanic origin and are formed as a result of solidification of molten mass lying below or above the earth’s surface.
The example are granite, syenite, diorite and gabbro.