Answer is: C₄H₈.
C₄H₈ is hydrocarbon, organic compound consisting only of carbon and hydrogen.
CaH₂ (calcium hydride) is alkaline earth hydride, inorganic compound.
H₂O₂(hydrogen peroxide) is pale blue, clear, inorganic liquid.
P₂O₅ (phosphorus pentoxide) is white, crystalline solid inorganic compound.