I think the appropriate orbital is the sp3 orbital. In ethanol the two C-H sigma bond are formed from overlap of carbon sp hybrid orbitals with hydrogen 1s atomic orbitals. The carbon-carbon sigma bond is formed from overlap of an sp3 orbital on each C atom. Thus Ethanol has 2(4) + 6(1) + 6= 20 e-. the two C atoms and the O atom are sp3 hybridized
