An internet service provider is testing its internet connection download speeds. A 1 gigabyte file is downloaded and the number of seconds it takes is recorded. This test is performed 20 times. The times in seconds are listed in the following table.

Download speeds (in seconds) for a 1 gigabyte file.
38 45 42 35 48
37 40 41 36 47
43 45 39 38 40
42 44 42 38 44
A. The sample mean is 41.2 seconds.
B. The sample mean is 38.6 seconds.
C. The sample mean is 40.4 seconds.
D. The sample mean is 39.2 seconds.