Take a look at the item again:
Because he had eaten a stack of twelve pancakes,
(A) Emanuel heard his
stomach begin to rumble (B)
as it processed the food. (C)
Gurgling loudly to protest the huge meal.
You wanted to to this:
Because he had eaten a stack of twelve pancakes, Emanuel heard his stomach
begin to rumble. As it processed the food.
Gurgling loudly to protest the huge meal.
Adding a period after rumble will make As it processed the food ... a fragment.
You might want to review the rules.
Go back to the sentence to try again.