(a) aqueous rock
(b) metamorphic rock
(c) sedimentary rock
(d) igneous rock
Ans :- (b) metamorphic rock

Explanation :-
Metamorphic rocks – Metamorphic rocks are formed igneous or sedimentary rocks as a result of the action of the earth movement, temperature changes, liquid pressure etc.
Exp. – Marble, Gneiss, quartzite etc.
Igneous rock- Igneous rocks form when magma (beneath the surface) or lava (reaches the surface) cools and hardens.
Exp. – Granite, Basalt, trap etc.