These functions use the cat() function to print a Multiple
Choice Question
in the GIFT format. In this questions, the user is asked to select one or
more answers. Use of the sink() function is adviced to send the ouput to a text
file.
If there are more than one right answer the length of anstxt and wright must be
the same. In addition, it one of the elements in wright is "100" then only one
answer can be chosen. Otherwise, the user can select several right answers (in
this case remember to use negative weights for the wrong answers!).