The correct option is D 2, 1, 2, 2 / 2, 1, 2, 2
The dental formula expresses the arrangement of teeth in each half of the upper jaw and the lower jaw. Humans below 17 years of age normally do not have the 3rd molar i.e. wisdom teeth. So the dental formula in an adolescent is 2,1,2,2 / 2,1,2,2 and the total number of teeth is 28.