A source of 10 V with an internal resistance of 5 Ω is to be connected through a converter to a load of 20 Ω. For maximum power transfer, what should be the turns ratio of the converter?

• A. 1 ∶ 2
• B. 1 ∶ 1
• C. 2 ∶ 1
• D. 1 ∶ 4