Correct answer is (a) Negative deviation
Explanation: Phenol and aniline both exhibit greater magnitude of hydrogen bonding due to the presence of hydroxyl and amine group, both possessing highly electronegative atoms of oxygen and nitrogen, respectively. The intermolecular hydrogen bonding is far greater than the degree of intramolecular hydrogen bonding which requires more thermal energy to break. Thus, there is an increase in the boiling point of the mixture.