The correct option is B CnH2n+2
The general formula of a non cyclic Alkane is CnH2n+2. Each carbon in the middle is connected to 2 Hydrogen atoms and the carbon atoms at the ends are connected to 3 carbons each. In case of a branched alkane, one of the hydrogens on a carbon is replaced by carbon, but that increases one more terminal carbon which connects to 3 hydrogens. So the general form CnH2n+2 remains the same(except for cycloalkanes).