The correct option is C (c)
The option, with the error in it, is the correct option.
Option C: The error lies in "at very high speed", because the article 'a' is missing here. Hence option C is correct.
Option A: There is no error in the part "My friend was"; it's in the past tense and agrees to the rest of the sentence. Hence option A is incorrect.
Option B: Similarly, the words "habitual to drive a car" also do not contain any error. ('habitual' is an adjective, 'to drive a car' is an infinitive phrase) Hence B is also incorrect.
Option D is incorrect because the error lies in C.