In the given bar graph, what is the ratio of students of A and B in the combine strength from 2016 to 2018?
1
23 ∶ 21
2
17 ∶ 16
3
21 ∶ 23
4
19 ∶ 20
In the given bar graph, what is the ratio of students of A and B in the combine strength from 2016 to 2018?