Two different metal rods of equal lengths & equal cross section area have their ends kept at the same temperatures \[{{\theta }_{1}}\And {{\theta }_{2}}.\] If \[{{K}_{1}}\And {{K}_{2}}\] be the thermal conductivities of rod, \[{{\rho }_{1}}\And {{\rho }_{2}}\] are their densities and \[{{s}_{1}},{{s}_{2}}\] are their specific heats, then the rate of flow of heat in the two rods will be same if

• A. \[\frac{{{K}_{1}}}{{{K}_{2}}}=\frac{{{\rho }_{1}}{{s}_{1}}}{{{\rho }_{2}}{{s}_{2}}}\]
• B. \[\frac{{{K}_{1}}}{{{K}_{2}}}=\frac{{{\rho }_{1}}{{s}_{2}}}{{{\rho }_{2}}{{s}_{1}}}\]
• C. \[\frac{{{K}_{1}}}{{{K}_{2}}}=\frac{{{\theta }_{1}}}{{{\theta }_{2}}}\]
• D. \[{{K}_{1}}={{K}_{2}}\]