Step 1: IT Act provisions.
The Information Technology (Amendment) Act, 2008 created the Indian Computer Emergency Response Team (CERT-In) as the national nodal agency for cyber security incident response.
Step 2: Section reference.
CERT-In is constituted under Section 70A of the IT Act, 2000.
Step 3: Role.
It handles cyber security threats, issues advisories, and coordinates incident responses.
Step 4: Conclusion.
Correct answer is (C) 70(a).