For this question, if answer choice B was 5\pi rather than 10\pi, would the answer choice have to be A?

My reasoning is this - since RT is a chord that does not pass through O, it must be less than the diameter. This means that the circumference must be greater than 5\pi.

I was wondering if there are any flaws in this logic. In the video, Greg explains that we do not have enough information to find the radius, but I think we do have enough information to find a lower bound for the radius/diameter.