I want to test your ability to explain.
I was thinking present, as in your ability to present — being able to give a good presentation.
That’s the only choice I can think of, but I feel there’s a better one. I googled it, but only received topics about improving how to explain thing.
cogent – convincing or believable by virtue of forcible, clear, or incisive presentation; telling.
It’s often applied to an argument (verbal presentation in favour of a particular concept) but it’s also commonly used of people who are good at presenting arguments, explanations, etc.