if W = {positive integers} and subset Z = {positive integers divisible by 5}, what is Z′?


{1, 2, 3, 4, …}


{ }


{5, 10, 15, 20, …}


{1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 16, …}