A

Step 1: Analyze the Circuit
In the circuit, we can see that there are resistors arranged in a parallel configuration between points C and B. Each resistor has a resistance of R = 1 Ω.

Step 2: Calculate Equivalent Resistance of the Resistors
The total number of resistors in parallel between points C and B is 4. The formula for calculating the equivalent resistance (R_eq) of n resistors in parallel is:
$$ \frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \frac{1}{R_4} $$
Since all resistors have the same resistance value (R = 1 Ω), we can simplify this to:
$$ \frac{1}{R_{eq}} = n \cdot \frac{1}{R} $$
Therefore, for 4 resistors:
$$ \frac{1}{R_{eq}} = 4 \cdot \frac{1}{1} = 4 $$
So, we have:
$$ R_{eq} = \frac{1}{4} \, \Omega $$

Step 3: Calculate Total Current
Now, we will use Ohm's Law to find the total current (i) supplied by the voltage source (U). Ohm's Law states:
$$ V = I \cdot R $$
Rearranging gives us the formula for current:
$$ I = \frac{V}{R} $$
Considering the voltage across the terminals U = 7 V and the equivalent resistance R_eq = 0.25 Ω, we get:
$$ I = \frac{7 ext{ V}}{0.25 ext{ Ω}} = 28 ext{ A} $$

Step 4: Conclusion
The current flowing through the leads is 28 A.
Therefore, the correct answer is A.