B) Although I purchased an automobile, I still didn't really feel grown up.
C) While I enjoyed purchasing an automobile, I would also have liked to have bought a house.
D) I purchased my first automobile on a cold, crisp November day.
Answer:
A) It was a cold, crisp November day when I purchased my first automobile.
Explanation:
A relativeclause starts with a relative pronoun
who/that
which/that
where
when
whose
There doesn't have to be a comma in between the relative pronoun and the rest of the sentence to make it a relative clause
C. A narrative that explains how an awful trip turned fun
D. A story explaining a series of silly accidents
b) The, the
c) an, -
d) -, the