Multiple selection options in a Multiple Choice field

Hi there

I am looking to create a question where the user is able make a section within one of the questions that allows the user will be able to make multiple selections of a number of options, e.g. select 6 options from a list of 40.

When I add a multiple choice element I only seem to be able to add 2 options because when I 'Add New' to the answers (it doesn't matter how many) once saved it only retains 2 options.

Please help