A recursive function column2list_rec(grid, n), where grid is a list of lists and n is an integer, that returns a list consisting of the element at position n of each row of grid. No for or while loops

[ [ 'aa', 'bb', 'cc', 'dd' ], [ 'ee', 'ff', 'gg', 'hh', 'ii', 'jj' ], [ 'kk', 'll', 'mm', 'nn' ] ]

1. column2list_rec(x,3) return value: ['dd', 'hh', 'nn' ]