I discovered gum wrappers pennies and a sock hidden under the seats when I vacuumed my car. The sentence above should be written as:
a. I discovered, gum wrappers pennies and a sock hidden under the seats, when I vacuumed my car.
b. I discovered gum wrappers, pennies, and a sock hidden under the seats when I vacuumed my car.
c. I discovered gum wrappers, pennies and a sock hidden under the seats, when I vacuumed my car.
d. No change.
