`Operation Sankalp` was an initiative taken by the Indian Navy which makes option 3 the correct answer. To understand why the other options are incorrect, let`s dissect them:

Option 1: Indian Air Force - This is incorrect because the operation was not related to air security but was for maritime security in the Gulf region, specifically the Strait of Hormuz and the Gulf of Oman, which is the mandate of the Navy, not the Air Force.

Option 2: Indian Army - Again, the army primarily conducts land-based operations. `Operation Sankalp` was a maritime operation aimed at ensuring the safety and security of Indian vessels in the region, which falls under the jurisdiction of the Indian Navy.

Option 4: Ministry of Home Affairs - This is also incorrect as the Ministry of Home Affairs mainly deals with the internal security and domestic policy issues in India. International maritime security operation such as Operation Sankalp falls under the purview of the Ministry of Defence, implemented by the Indian Navy.