What countries cities capital is quito?

Your English Grammar is rather poor.

The question should read , What country's capital city is Quito?'

Note the disposition of the Words, and the spelling of 'country's' ; possessive adjective; you gave the plural noun. The plural noun would suggest that there are several countries , with 'Quito' as a capital city. There is only one country and it is 'Ecuador'.

The answer to your question is 'Ecuador'.