The researchers carried out experiments on 40 college students. They asked these students to memorize English words corresponding to Swahili. There were ten groups, each with ten pairs of vocabulary, and after each group was learned, participants were given a recall test, a test Each time they make a mistake, they will see one of two pictures. One is a picture that can generate negative emotions, such as a gun pointing at themselves. The other is a normal picture, such as a chair or A blank image. Then they performed an additional one-minute experiment on them to clear the effect of short-term memory. Finally, they tested the memory of the hundred pairs of vocabulary. The test results showed that the students who got the best scores were watching before Pictures that have a negative effect. Therefore, researchers believe that negative emotions help improve memory. Which of the following, if true, could explain this phenomenon? ['When looking at pictures with negative effects, the brain is still processing memory information.', 'Some of the 40 college students who have studied Swahili.', 'Pictures that can trigger negative emotions are more likely to make people remember.', 'People have difficulty concentrating when their mood is unstable.']