Country A is said to dominate B or A > B if A has higher percentage in total coverage for both drinking water and sanitation facilities, and, B is said to be dominated by A, or B < A.
So from the table we can see that :-
A country is said to be on the coverage frontier if no other country dominates it. Similarly, a country is not on the coverage frontier if it is dominated by at least one other country.
So India is not on the coverage frontier because India is Dominated by Bangaladesh and Philippines
Answer: option D