Why is it sometimes difficult for ecologists to design controlled experiments?

Your two friends just told you what to order for them at the drive through fast food restaurant. you give the order but when the food comes about 10 minutes later, you don't remember what each of your friends ordered your memory of the order was in __ memory. a. semantic b. flashbulb c. long-term d. short-term i think i know but i'm not really sure