Explanation: In a Class A amplifier, the active device (tube, transistor, etc.) is biased so that output current flows for the entire 360 degrees of the input signal cycle. Option A is correct because, in a properly designed Class A amplifier, the control grid (for a vacuum tube) or gate/base (for a transistor) is biased such that the input signal never drives it positive enough to draw current. Drawing grid current would introduce distortion and load the preceding stage. Therefore, the input impedance remains high and linear. Option B is incorrect. Plate current flows for the *entire* 360 degrees of the cycle in a Class A amplifier. If current flowed slightly more than 180 degrees, it would describe Class AB operation, not Class A. Option C is incorrect because "biased to twice" is not a standard or meaningful term in the context of amplifier biasing. Class A is simply biased to operate in the linear region for full 360-degree conduction.