A sum of Rs. 1550 was lent partly at 5%and partly at 8%p.a. simple interest.The total interest received after 3 years was Rs. 300. The ratio of the money lent at 5%to that lent at 8%is:

• A. : 8
• B. : 5
• C. 6 : 15
• D. 1 : 6