$U_{rms}\;\;\;H_2 = \sqrt{[\large\frac{3\times50\times R}{2}]}$

$U_{rms}\;\;\;O_2 = \sqrt{[\large\frac{3\times800\times R}{32}]}$

$\therefore \large\frac{U_{rms}H_2}{U_{rms}O_2} = \large\frac{3\times50\times32}{2\times3\times800}$

$\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;=1$

Hence answer is (c)