Answer:
B) 2.2 Ω
Explanation:
The resistor between B and C is connected in parallel to the resistor between C and D (because their ends are connected to the same points: C on one side and B (which has same voltage as D) on the other side, so they have same potential difference across them.
So their equivalent resistance is
[tex]\frac{1}{R_{BD}}=\frac{1}{R_{BC}}+\frac{1}{R_{CD}}=\frac{1}{4.0 \Omega}+\frac{1}{5.0 \Omega}=\frac{9}{20 \Omega}\\R_{BD}=\frac{20 \Omega}{9}=2.22 \Omega[/tex]
The resistor between A and B, instead, is short-circuited, because the current flows through the upper branch of the circuit (connecting A with C), which has zero resistance (it is a wire without any resistor). This means that the resistor between A and B should not be considered: so, the total resistance of the circuit is
[tex]2.2 \Omega[/tex]
