The difference in length between two rods \(A\) and \(B\) is 60 cm at all temperatures. If \(\propto_A=18 \times 10^{-6} /{ }^{\circ} \mathrm{C}\) and \(\propto_B=27 \times 10^{-6} /{ }^{\circ} \mathrm{C}\), then the length of \(\operatorname{rod} A\) and \(\operatorname{rod} B\) at \(0^{\circ} C\) is respectively

1. A \(\ell_{\mathrm{A}}=120 \mathrm{~cm}, \ell_{\mathrm{B}}=60 \mathrm{~cm}\).
2. B \(\ell_{\mathrm{A}}=180 \mathrm{~cm}, \ell_{\mathrm{B}}=120 \mathrm{~cm}\).
3. C \(\ell_{\mathrm{A}}=240 \mathrm{~cm}, \ell_{\mathrm{B}}=180 \mathrm{~cm}\).
4. D \(\ell_{\mathrm{A}}=270 \mathrm{~cm}, \ell_{\mathrm{B}}=210 \mathrm{~cm}\).