BC546s can be obtained in A, B or C-grade, with as main difference the current gain:
The circuit schematic below — of a crappy FM transmitter [2] — does not indicate whether the BC547 should be type A, B or C, so the current gain of this transistor is very uncertain. This leads to an uncertain collector current and consequently uncertain voltage across the resistor in the circuit schematic. For proper operation of the BC547, its must be larger than about 100mV and should not be very close to . Calculate whether this is the case for all types (A,B,C) of the BC547.