Which one of the following statements is correct in respect

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Which one of the following statements is correct in respect of BJT?

1. Avalanche multiplication starts when the reverse biased collector-base voltage V_CB equals the avalanche breakdown voltage BV_CBO
2. The early effect starts as soon as punch-through occurs in a transistor
3. The small signal current hfe = large signal current gain hFE when h_FE/ I_C = 0
4. In the CE mode, transistor can be cut off by reducing I_B to zero

Correct Option: A

Avalanche multiplication starts when the reverse biased collector-base voltage VCB equals the avalanche breakdown voltage BVCBO. We know that the maximum reverse-biasing voltage which may be applied before breakdown between the collector and base terminals of the transistor, under the condition that the emitter lead be open circuited is represented by the symbol BVCBO. This breakdown voltage is a characteristic of a transistor alone, breakdown may occur because of avalanche multiplication of the current I_CO that crosses the collector junction.