Study the following graph that shows the number of boys and girls who appeared for the Class X examination in a school XYZ, in different years.

What is the ratio of the total number of girls who appeared in 2012 and 2015 to the total number of boys who appeared for the class X examination in 2012 and 2013?

A

11:13

B

15:11

C

11:15

D

13:11