500
47. Only tenth, eleventh, and twelfth-grade students attend Washington High School. The ratio of tenth graders to the school's total students population is 86.255, and the ratio of eleventh graders to the school's total student population is 18:51. If 1 student is chosen at random from the entire school, which grade is that student most likely to be in?
A. Tenth
B. Eleventh
C. Twelfth
D. All grades are equally likely
E. Cannot be determined from the given information.