Final answer:
The sentence should be completed with 'about / bake,' indicating to not forget about an additional action concerning the oven after the pie is baked.
Step-by-step explanation:
The question 'Don't forget __the over after___the pie.' is asking to choose the correct pair of prepositions that best complete the sentence. In English language learning, understanding prepositions and their usage is important for constructing sentences with correct meaning. The correct answer is B. 'about / bake.' Therefore, the complete sentence would be 'Don't forget about the over after baking the pie.' In this context, 'about' is used to remind someone to consider something, and 'after' is used to refer to something that happens subsequent to another action.