Answer:
B. a handout
Step-by-step explanation:
If Allan is giving a presentation, and he wants the audience to be able to access the information once this presentation is over, then he should use handouts as visual aid. This will be useful for the audience because they will be able to take it home and look at it again. On the other hand, a demonstration or a wall poster are two types of aid that can only be accessed during the presentation.