Step 1: Resistance in a cube.
The total resistance between diagonally opposite corners of a cube formed by 12 resistors is \( \frac{5}{12} \) times the resistance of a single resistor. Hence, the equivalent resistance is 5 ohms.
Step 2: Conclusion.
Thus, the correct answer is option (D).
Final Answer:
\[
\boxed{5 \, \text{ohms}}
\]