# What volume of oxygen gas ($O_2$) measured at $0^{\circ}C$ and 1 atm, is needed to burn completely 1L of propane gas $(C_3H_8)$ measured under the same conditions?

$\begin {array} {1 1} (1)\;10L & \quad (2)\;7L \\ (3)\;6L & \quad (4)\;5L \end {array}$