How to find the respective sets according to the minimum cost

one set is S1( 7,4,3,9,2)

another one S2 ( 3,6,7,1,8)

cost1 = 20 // respective to S1

cost2 =23 // respective to S2

A = min[ cost1; cost2];// cost1 having minimum value

how to find the respective set S1 after finding the minimum cost