A message signal given by \(m\left( t \right) = \frac{1}{2}\cos {\omega _1}\left( t \right) - \frac{1}{2}\sin {\omega _2}t\)is amplitude modulated with carrier of frequency \({\omega _c}\) to generate \(s\left( t \right) = \left[ {1 + m\left( t \right)} \right]\cos {\omega _c}t\) .What is the power efficiency achieved by this modulation scheme?

• A. 8.33%
• B. 11.11%
• C. 20%
• D. 25%