The correct answer is C. forever.
Option A is incorrect because it is possible to leave a country for better opportunities and then return. Option B is incorrect because it is possible to be on an important mission and then return. Option D is incorrect because it is possible to leave a country and then return.
The sentence “Govind has left his country for good” means that Govind has left his country and does not intend to return. This could be for a number of reasons, such as finding better opportunities in another country, or wanting to start a new life.