how to specify which matrix i use

hello folks. i have a general programming question. I have a matrix lets say D. In regression its called the design matrix. I want to apply some functions in all possible submodels for regression. The design matrix for each of those sub models consists of a subset of columns of D. I used

C=arrayfun(@(x) D(:,logical(dec2bin(x,qq)-'0')), 1:2^qq-1, 'unif', 0);
C{:};.

This way i created a cell matrix C whith elements all possible combinations of columns taken from D. So, i want to apply some functions in each element(matrix) of C. My question is how can i know for each element of C which columns are used from D. i.e. i want a function or something that will tell me that C{1,3} contains the matrix that consists of columns 1 and 2 of D for example.

Thanks for your time.