Julia wants to be sure that she can listen effectively to the speaker at the town hall meeting. which strategy will her succeed? jumping to conclusions? multi-tasking during the speech? prejudging the speaker? researching the topic in advance?

Don't jump to conclusions, you'll lose interest and have a bias opinion already in the way.
If you multitask you are dividing your attention and not hearing everything the speaker has to say.
Prejudging and jumping to conclusions are the same thing.
So i would research the topic in advance, so you would already have questions to ask and have a further understanding of the topic.