An amendment to the constitution can be initiated by the introduction of a bill in either House of Parliament. This means that members of either the Lok Sabha or the Rajya Sabha can propose a bill to amend the constitution.

Option 1, which states that the amendment can be initiated by the President of India, is incorrect. The President does not have the power to initiate an amendment to the constitution.

Option 2, which mentions the Rajya Sabha, is also incorrect. While the Rajya Sabha can play a role in the amendment process by voting on the bill, it does not have the power to initiate the amendment.

Option 3, which suggests that the Governors of States can initiate an amendment, is also incorrect. The Governors do not have this power.

Therefore, option 4 is the correct answer as it correctly states that an amendment can be initiated by the introduction of a bill in either House of Parliament.