3. A transistor is operated in common-emitter configuration at \( \mathrm{V}_{c}=2 \mathrm{~V} \) such that a change in the base current from \( 100 \mu \mathrm{A} \) to \( 200 \mu \mathrm{A} \) produces a change in the collector current from 5 \( \mathrm{mA} \) to \( 10 \mathrm{~mA} \). The current gain is:
1) 100
2) 150
3) 50
4) 75
