Urgent timed test which data set is the most clustered around its mean? .. a.10, 30, 40, 20 b.12, 14, 36, 38 c.8, 42, 30, 30 d.30, 25, 15, 30

The sum of all numbers, in every one of the options is 100.the mean would 100/4, since all options gives you 4 numbers.that said, the mean would be 25.  i would say option d.30 25 15 30