Asked by AKSHAY GURU VARADHARAJAN · SRI CHAITANYA TECHNO SCHOOL, JAYANTI NAGAR.
Answer: C. Magma.
Magma is the hot, melted rock deep inside the earth. When it cools it forms igneous rocks, the first or primary rocks, from which all other rocks are later made. So magma is the source of all rocks.
Answering after opening this box earns no Practice Points.