This answer is not correct. The attractive interactions between alkanes are dispersion forces which are rapidly fluctuating weak dipoles of the carbon-hydrogen bonds. Another factor that must be considered regarding the boiling points of alkanes is mass. These compounds all have the same mass. Molecules must have many dispersion force interactions in order to increase the boiling point. Fewer of this interactions are possible as the branching of the hydrocarbon increases. A test-taking hint...whenever faced with a series of homologous answers, the middle answers are usually not correct...go with one extreme or the other.