Correct Answer: maintain

Solution : The correct answer is 'maintain'.
Key Points
- The most appropriate word for the mentioned blank is 'maintain'.
-To make anything at the same level, standard, etc.,

When we maintain something, we keep it going and don't allow it to falter or get weaker.
- The purpose of the sentence is to convey the idea that maintaining communal harmony is everyone's responsibility in India.
- Therefore, the word "maintain" is appropriate in the context.
Correct Sentence: It is the moral duty of every Indian to maintain communal harmony.

Meaning of the other words are as follow:
Give: to provide.
Repair :  means something to restore it to its original, undamaged state.
Obtain: to get.