To describe that an action has never been done before, we use a type of the tense, called the ‘past perfect tense’. The pluperfect, also called the pluperfect tense, could be a tense accustomed discuss actions that were completed before some point within the past. the right tenses include the helping verbs ‘have’, ‘has’, and ‘had’.
The given sentence is within the past. So, we must use the past perfect tense tense here.

The pluperfect tense is built within the following way: had + perfect participle.

For example, the verb ‘eat’ would be conjugated in perfective tense as ‘had eaten’.
Now, let’s have a look at the given options:

a)is never flying - This phrase contains the word ‘is’ which signifies that it's present. the foundation verb ends in ‘-ing’. This phrase is within the present imperfect tense. So, this can be an incorrect option.
b)has never flown - This phrase contains the word ‘has’, together with the participle ‘flown’. This signifies that it's within the perfective tense. So, this can be an incorrect option.

c)had never flown - This phrase contains the word ‘had’, and therefore the participle ‘flown’. This signifies that this can be within the perfect tense. So, this is often the right option.
d)was never flying - This phrase contains the word ‘was’, which means it's the past, and also the root verb ends in ‘-ing’. this can be within the past progressive tense. So, it's an incorrect option.

Note: pick the acceptable tense in conjunction with the word ‘was’ from the primary sentence.