For smooth and reliable operation of an amplifier using BJT, it is necessary that the circuit must be properly designed from the point of view of bias stabilization, because:1. Reverse saturation current ICO increases with rise in temperature.2. VBE decreases with rise in temperature.3. hFE or β changes with change of temperature and replacement of the transistor.4. hFE or β changes with change in collector supply voltage.

For smooth and reliable operation of an amplifier using BJT, it is nec

1.	For smooth and reliable operation of an amplifier using BJT, it is necessary that the circuit must be properly designed from the point of view of bias stabilization, because:1. Reverse saturation current ICO increases with rise in temperature.2. VBE decreases with rise in temperature.3. hFE or β changes with change of temperature and replacement of the transistor.4. hFE or β changes with change in collector supply voltage.
A.	1, 2 and 3 only
B.	1, 2 and 4 only
C.	2, 3 and 4 only
D.	1, 2, 3 and 4
Answer» B. 1, 2 and 4 only