The small signal input impedance of a transistor whose output is shorted for the measuring signal is

• A. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-1.png">
• B. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-2.png">
• C. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-3.png">
• D. <img src="/_files/images/electronics-and-communication-engineering/electronic-devices-and-circuits/49-298-4.png">