Assigning Point Values - Options not available in Quizmaker 13'

I am working in Quizmaker 13' and do not have the same options when selecting the drop down below. My only choice is "By Question". The other two options, "None" and "By Choice"  do not appear for me to select.  I need to have the ability to select "By Choice", but it is not listed in my drop down menu as an option.

What can I do to have the have  "None" and "By Choice" list as choices in my drop down?