In the circuit shown the op-amp has finite input impedance, infinite voltage gain, and zero input offset voltage. The output voltage $V_{out}$ is
1. $-I_{2}(R_{1} + R_{2})$
2. $I_{2}R_{2}$
3. $I_{1}R_{2}$
4. $-I_{1}(R_{1} + R_{2})$