Efficiency of general AM signal with em = E1 cos 1t + E2 cos 2 tj ec = Ec cos ct; E1 cos 1t with modulation index m2 is __________ .

• A. <img src="/_files/images/electronics-and-communication-engineering/communication-systems/539-1020-1.png">
• B. <img src="/_files/images/electronics-and-communication-engineering/communication-systems/539-1020-2.png">
• C. <img src="/_files/images/electronics-and-communication-engineering/communication-systems/539-1020-3.png">
• D. <img src="/_files/images/electronics-and-communication-engineering/communication-systems/539-1020-4.png">