Feature Request: Multiple choice question #464

Feature description

Thanks for your tools, they have helped us a lot. I wonder if you will add support for multiple-choice annotations. Here is an example：
Question:

The capital of the China?

Options:

A. XXX
B. XXX
C. XXX

The number of opetions is not always the same for questions.
The user could select one option when annotation.

Currently we could use Seq2Seq annotation to do this but it is not so convenient.