An education services company that offers tutoring for children (as young as one-year-old) and adults present a graphic in their pamphlet. What is the best claim that can be supported by the graphic

A. 40-year-olds need at least 45 hours of study to improve
B. College students represent the smallest portion of the clients
C. Children between 10 and 15 years of age increase their scores up to 35%
D. Tutoring adults who are over the age of 21 accelerates their learning significantly