A researcher measured the height of each toddler in a study. Here are their heights: a dot plot has a horizontal axis labeled, height, in centimeters, marked from 80 to 86, in increments of 1. The number of dots above each value is as follows: 81, 1; 82, 1; 83, 2; 84, 2; 85, 2. Find the median height. 
a. 83 cm 
b. 84 cm 
c. 85 cm 
d. 86 cm