Currently, the option has to correspond to a number key. Specifically, the numbers 1 through 9 or the F1 through F12 keys, the latter corresponding to options 1 through 12. It is on our to-do list to allow for alternate key mapping--i.e., to be able to specify alternate keys which will be regarded as valid responses for any given option.

See also cautionary notes re response labels:
www.empirisoft.com/support/showthread.php?t=334
www.empirisoft.com/support/showthread.php?t=345