The correct statement is: Substance B has stronger bonds, and it takes more energy to undergo a phase change.
Since Substance B has a higher boiling point (100ºC) compared to Substance A (78.4ºC), it indicates that Substance B has stronger intermolecular forces (such as hydrogen bonding) that require more energy to break during the phase transition from liquid to gas. Therefore, Substance B has stronger bonds and takes more energy to undergo a phase change.