Karen doesn't like driving to the local bank branch, but doesn't think that it is secure to do financial transactions on her phone. what is the best banking option for her?

The best answer would be online banking and only use her local bank when necessary.

Online banking allows users to do bank transaction over the internet from the comfort of your home. Although there are still some risks to online banking, many banks have already adapted safety measures which have improved the system a lot. 

Mobile banking is also an option but it can also pose a great threat if she leaves her phone unattended or if it gets lost.