It Is a Sunny Day,and Tom Is Stopped at a Light

It is a sunny day,and Tom is stopped at a light at a four-way intersection in the city waiting for the light to change.Mary,stopped behind him,accidentally lets her foot slip off the brake,and her vehicle bumps into Tom's vehicle.The fact that it is a sunny day is most likely a:

A) Key fact
B) Background fact
C) Secondary fact
D) Primary fact
E) None of the above
F) Answers b and c above
G) Answers a and c above