Two silicon diodes, with a forward voltage drop of $0.7 \: V$, are used in the circuit shown in the figure. The range of input voltage $V_i$ for which the output voltage $V_o=V_i$, is
- $-0.3 \:V < V_i < 1.3 \: V$
- $-0.3 \:V < V_i < 2 \: V$
- $-1.0 \:V < V_i < 2.0 \: V$
- $-1.7 \:V < V_i < 2.7 \: V$