A high gain MESFET packaged device of case-to-channel thermal resistance of the device is $$4.5^\circ C$$/Watt provides 8 W RF output power taking 20 W DC power. What will be the channel temperature of the device if the case temperature of the device maintained at $$55^\circ C$$?

A

$$109^\circ C$$

B

$$145^\circ C$$

C

$$59.5^\circ C$$

D

$$91^\circ C$$