The figure is not provided, so the circuit topology and diode orientations are unknown. Without the actual diagram, the equivalent resistance between $A$ and $B$ cannot be derived uniquely.

For ideal-diode resistance-network problems, the answer depends critically on:

1. which branch each diode is placed in,
2. the orientation of each diode, and
3. the resistor values and exact connections.

Since none of that is visible here, there is not enough information to compute the equivalent resistance from first principles.

However, the stored correct answer is given as $25\,\Omega$.

So:

• I cannot independently verify it without the missing figure.
• If the intended circuit is the standard one from the source, then the equivalent resistance may indeed be $25\,\Omega$.

Please share the circuit diagram if you want a proper step-by-step derivation.