Combustion of carbon compound

1. We note that $\ce{C3 H8 + 5O2 -> 3C O2 + 4H2 O}$ is a balanced reaction equation. Also note that $\ce{C3H8}$ is a saturated hydrocarbon and $\ce{C_{3n}H_{8n}}$ for $\ce{n} > 1$ is impossible. Therefore $\ce{X}$ is $\ce{C3H8}$ and $\color{#3D99F6}{\text{a) is correct}}$ .
2. The volumes of gas mixture before and after the reaction are $6$ L and $7$ L respectively. Therefore, the volume of the gax mixture is increased after the reaction and $\color{#3D99F6}{\text{b) is correct}}$ .
3. One mole or $160$ g of oxygen is required for one mole or $44$ g of $\ce{C3H8}$ . Therefore, the mass of oxygen required for a complete combustion of $4.4$ g of $\ce{C3H8}$ is $16$ g and $\color{#3D99F6}{\text{c) is correct}}$ .

$\Rightarrow \boxed{\text{a), b) and c)}} \text{ are correct.}$