Which of the following azeotropic solutions has the boiling point less than the boiling point of its constituents molecules?

When the new interaction is weaker than those in the pure constituents, the boiling point of the resultant solution is less than that of the constituents. Such condition is found in case of non-ideal solution showing positive deviation from Raoult's law. Among the given solutions, mixture of CH3CH2OH and CH3COCH3 is non-ideal and show positive deviation. Hence. it has lesser boiling point or higher vapour pressure, than its constituents.