The correct answer is option 'C', which states that "Link-state response" is not a type of OSPF packet.

Explanation:
OSPF (Open Shortest Path First) is a routing protocol that is commonly used in computer networks to determine the best path for routing IP packets. OSPF uses various types of packets to exchange information and maintain the routing tables.

Below are the different types of OSPF packets:

a) Hello Packets:
- Hello packets are used for neighbor discovery and maintenance in OSPF.
- These packets are sent periodically to establish and maintain neighbor relationships.
- Hello packets contain information such as the router ID, the area ID, and other parameters.

b) Link-state request packets:
- Link-state request packets are used to request specific link-state information from neighboring routers.
- These packets are sent when a router needs to acquire additional information about a particular link or router.

c) Link-state response packets:
- Contrary to the given statement, "Link-state response" is not a type of OSPF packet.
- OSPF does not have a specific packet type called "Link-state response".
- This option is incorrect because it does not correspond to a valid OSPF packet type.

d) Link-state acknowledgment packets:
- Link-state acknowledgment packets are used to acknowledge the receipt of link-state advertisements (LSAs).
- When a router receives an LSA, it sends a link-state acknowledgment packet back to the sender to confirm the successful receipt.

In summary, the correct answer is option 'C', as "Link-state response" is not a valid type of OSPF packet. OSPF uses hello packets, link-state request packets, and link-state acknowledgment packets for various functions within the protocol.