For all of my life, I have been a jogger. I first ran the Peachtree Road Race, a famous 10-kilometer race in Atlanta, ___________. Later I competed in both cross country and track in high school, before earning a track scholarship to attend Georgia Tech.

Fill in the blank with the correct answer.
A) I was ten years old.
B) very soon I was ten years old.
C) because I was ten years old.
D) when I was ten years old