Here is the original item:
Karlene drove slowly through the heavy
traffic. (A)
Anticipating a bag of microwave
popcorn (B)
and a couple of hours in front of the
television (C)
as her reward for a hard day at work.
You wanted to do this:
Karlene drove slowly through the heavy traffic. Anticipating a bag of microwave
popcorn,
and a couple of hours in front of the television as her reward for
a hard day at work.
Adding a comma after popcorn causes a problem. You do not use a comma with and when you are connecting only two items.
You might want to review the rules.