All three are strictly speaking organic straight chain compounds. Branched chain compounds are those which have a main chain of carbon atoms with an alkyl group attached to at least the second carbon in the main chain.
Methane is CH4 with no side chain.
Chloroform is CHCl3 again no side chain.
Acetic acid (correct IUPAC name ethanoic acid) is CH3COOH, and although the =O or -OH may appear to be branched this is not an example of a branched chain compound.