For the operational amplifier circuit shown, the output saturation voltage are $\pm 15 \:V$. The upper and lower threshold voltages for the circuit are,respectively,
- $+ 5 \: V$ and $– 5 V$
- $+ 7 \: V$ and $– 3 \: V$
- $+ 3 \: V$ and $- 7 \: V$
- $+ 3 \: V$ and $– 3 \: V$