The combustion product of the given organic compounds is carbon dioxide ($\text{CO}_2$). In $\text{CO}_2$, the central carbon atom is bonded to two oxygen atoms via double bonds ($\text{O=C=O}$), so it has $sp$ hybridisation.

Let's evaluate the hybridisation of the carbon atoms in the given options:

1. Ethane ($\text{CH}_3\text{-CH}_3$): The carbon atoms form only single bonds and are $sp^3$ hybridised .
2. Ethyne ($\text{HC}\equiv\text{CH}$): Each carbon atom forms a triple bond and is $sp$ hybridised .
3. Ethene ($\text{CH}_2\text{=CH}_2$): The carbon atoms form a double bond and are $sp^2$ hybridised .
4. Ethanol ($\text{CH}_3\text{CH}_2\text{OH}$): The carbon atoms form only single bonds and are $sp^3$ hybridised.

Therefore, ethyne has the same $sp$ hybridisation as $\text{CO}_2$.