Reduction of multiple answers to single variable The questionnaire for the data is here

The first question takes multiple entry for the same question, I want to reduce this to a single variable. How do I do it?

The clean data is available here.
NB: The Column CompuPlat has missing values.

part of dataset

CMFam CMHobb  CMNone  CMOther CMPol   CMProf  CMRel
0   0   1   0   0   0   0
0   0   0   0   0   0   0
1   1   0   0   0   1   0
0   0   0   1   0   0   0
0   0   0   0   1   1   0
1   0   0   0   0   1   1
Community Membership_Family
Community Membership_Hobbies
Community Membership_None
Community Membership_Other
Community Membership_Political
Community Membership_Professional
Community Membership_Religious
Community Membership_Support

I want to club all of them in a variable CM
The variable represents the answer to the first question. 

One straightforward way is to allow for all possible categories in this variable. For example, if there are 5 options in this answer, you will have to treat it as a categorical variable with 2^5 = 32 categories. 

However, the number of categories increase exponentially with the number of options (check boxes) provided for the answer. In that case, it might be better to restrict the number of categories to, for example, 5. This can be done by leaving the top 4 choices/ options (by count) as they are and treating every other choice as "other".