Below is an example of a workflow process where a user will be updating certain accounts based on their settings.
What is the best way to label options that can be true / false or both? (Seen in the "Account Activity" radio set)
If you mean that you're trying to filter results by account with activity, without activity, or include all accounts, you can do it a number of ways. Most importantly though, you want to make it clear what you're doing (it is unclear in your wireframe that you're filtering rather than selecting one of three options). How you present the filtering option will depend on the context (for example, is there only one filter or are there many filters?).
Option 1: Amazon style labels
When a user clicks on either of the options, you should show what they're filtered by somewhere on the page, e.g., in a breadcrumb, with a list of filters, etc.
Option 2: Checkboxes
When no checkboxes (or all checkboxes) are selected, everything is shown. If one box is selected, filer by that option. This is common behaviour for filtering (see Amazon).
Option 3: Dropdown filter
This is probably your best option if there is only one filter criteria. The disadvantage of this is that it's multiple clicks to select a single option. The advantage is that it's clear what's happening.
Or you could just change the labeling from "Account activity" to something like "Show accounts that" and change the selectable options to "have activity", "have no activity", "Both".