Correct answer: 8/3 ohm
The 12 ohm wire is divided equally into three sides, so each side has resistance 4 ohm. Between any two corners, one path is 4 ohm and the other path is 8 ohm in series. These two paths are in parallel, giving \(R_{eq} = \frac{4 \times 8}{4+8} = \frac{8}{3}\,\Omega\).