Answer:
While I was smoking my cigar, a fire engine came roaring around the corner.
Explanation:
In the third option it's showing the time when the fire engine came and that too in correct form of words.
A is the answer to your question
The answer is both a and b
Nick characterizes the mind of Jay as the mind of god meaning that he believed that he could do anything he dreamed of
Graham Greene, The Evening Redness In The West