Is there any way to amend the options available in one question based on the response in the previous question?

We are a high school wanting to allow students to submit their subject choice by electronic means - but if the student selects a particular subject in Option A, then other subject(s) in Option B are no longer available for selection. 

Is it possible to amend the options available in question 2 based on the answer selected in Question 1?

The Dynamic Dropdown widget sort of does this, but the nested tree quickly becomes very complex, and when an error arises, it is difficult to figure out what is causing the problem - I think it would be easier to control with some sort of IF logic statements.

Unfortunately, we cannot remove an option in the dropdown based on condition.

You may however, hide/show a field based on condition.

You can have different dropdown fields with different options.

https://www.jotform.com/help/316-How-to-Show-or-Hide-Fields-Base-on-User-s-Answer

Please check it out and let us know if this fits your requirements.