To determine the total current 'I' supplied by the voltage source, we need to find the equivalent resistance of the circuit and then use Ohm's Law.

1. The circuit consists of a configuration known as a balanced Wheatstone bridge. The middle resistor can be ignored if the bridge is balanced, as it doesn't affect the equivalent resistance.
2. All resistors are of 3 Ω. Let's calculate the equivalent resistance seen by the source:

Step 1: Ignore the Central Resistor: The two pairs of resistances (top and bottom) are in series, each pair having a total resistance of \(3\, \Omega + 3\, \Omega = 6\, \Omega\).

1. These two 6 Ω resistors are in parallel. The equivalent resistance \(R_{\text{eq}}\) is given by:

\(R_{\text{eq}} = \frac{R_1 \times R_2}{R_1 + R_2} = \frac{6 \times 6}{6 + 6} = \frac{36}{12} = 3\, \Omega\)

1. Step 2: Apply Ohm's Law (Voltage = Current × Resistance): The source voltage is 15 V.

The current \(I\) supplied by the source is:

\(I = \frac{V}{R} = \frac{15}{3} = 5\, A\)

1. Therefore, the total current supplied by the voltage source is 5 A.

This matches option 5, which is the correct answer.