A sleep time of 15.9 hours per day for a newborn baby is at the 10h percentile of the distribution of sleep times for all newborn babies. Assuming the distribution is normal with a standard deviation of 0.5 hour, approximately what is the mean time, in hours per day, for newborn babies?
A. 15.1
B. 15.3
Ğ¡. 16.3
D. 16.5
E. 16.7