The correct option is 2. The correct statement is that the doctrine of cold start is a defensive doctrine to respond to Pakistani attack on Indian territory.

Option 1 is incorrect. The doctrine of cold start indeed involves joint operations between India`s three services (army, navy, and air force) and integrated battle groups. This is aimed at enhancing cooperation and coordination among the different branches of the military.

Option 3 is incorrect. The doctrine of cold start was not launched in the year 2004. While the concept of cold start gained prominence around that time, it is more of a strategic doctrine and not a specific initiative or launch in a particular year.

In summary, only statement 2 is correct, which states that the doctrine of cold start is a defensive doctrine in response to a Pakistani attack on Indian territory.