Solution:

Short answers are brief and curt answers. We use short answers as sometimes, things demands that our answers be formal and saying only yes or only no can seem rude.
Before learning short answers, we must have some concepts in situ.
Firstly, we want to understand the difference between the auxiliary verb and therefore the main or the conjugated infinitive verb.
The auxiliary verb is additionally referred to as the helping verb.
Conjugation means to create the topic match the verb.
The infinitive is that the ‘to form’ of the verb.
Auxiliary verbs precede the conjugated verb.
When a matter is asked with the auxiliary verb in situ, the solution must always have the auxiliary verb first. The conjugated verb may or might not follow.
Let us examine the choices given to us.
Option ‘a’ Yes they live - this selection is wrong because the auxiliary verb is missing.
Option ‘b’ No, they don’t have - this selection is wrong because the verb has been changed and negated.
Option ‘c’ Yes, they are doing - this feature is true because it has the correct auxiliary verb.
Option ‘d’ No, they aren’t - this selection is wrong because the verb has been changed and negated.
Hence option ‘c’ is that the correct answer.