The number of snails in a given Alabama creek bed by each of 30 segments of the creek is as follows:

32, 6, 21, 10, 8, 11, 12, 36, 17, 16, 15, 18, 40, 24, 21, 23, 24, 24, 29, 1, 4, 9, 32, 23, 40, 15, 29, 25, 33, 20

What is the median number of snails of the 30 segments of this Alabama creek?

24

23

21