The ratio between the present ages of A and B is 5:3 respectively. The ratio between A's age 4 years ago and B's age 4 years hence is 1:1. What is the ratio between A's age 4 years hence and B's age 4

• A. 3 : 1
• B. 3 : 5
• C. 3 : 7
• D. 3 : 9