The ratio between the parents ages of A and B is 5 : 3 respectively. The ratio between A's age4 years ago and B's 4 years hence is 1 : 1. What is the ratio between A's age 4 years hence and B's age 4 years ago ?

• A. : 3
• B. : 1
• C. : 1
• D. : 1
• E. one of these