Combination of Resistors question from JEE Main 2023 (8 Apr, Shift 2)

Answer: (c)

1. The top wire joins A to D, and the bottom wire joins C to B.
2. So $20\text{ k}\Omega$ (A–C), $20\text{ k}\Omega$ (C–D) and $10\text{ k}\Omega$ (D–B) are each directly between A and B: all in parallel.
3. $\dfrac{1}{R} = \dfrac1{20} + \dfrac1{20} + \dfrac1{10} = \dfrac15 \Rightarrow R = 5\text{ k}\Omega$
4. So the answer is (c) $5\text{ k}\Omega$.