The ratio of the number of boys and the number of girls in a school is 7 ∶ 8. If the percentages of increase in the number of boys and the number of girls are 20% and 10% respectively, what will be the new ratio of the number of boys and the number of girls?

• A. 8 : 9
• B. 17 : 18
• C. 21 : 22
• D. 22 : 27