Answer: A) find a better place to study, B) put ideas into his own words and D) study when he is not tired.
Explanation: when we are studying, there are many factors that can have an influence in our performance and memory. In the given example, if Peter is having trouble memorizing some ideas in the text about science, he could find a better place to study (with as little distractions as possible), put ideas into his own words (in this way he will learn them more easily) and study when he is not tired (because sometimes being tired affects our memory).
