Option 1 -> ambiguous means unclear or open to multiple interpretations, unrelated to generosity.
Option 2 -> peevish means irritable or easily annoyed, opposite of a generous gesture.
Option 3 -> reverent means showing deep respect or admiration, not related to generosity.
Option 4 -> liberal means generous in giving, synonymous with munificent.
Hence, Option 4: liberal -> Munificent means extremely generous or lavish in giving, and liberal (in this context) shares the same meaning of being generous and open-handed with resources or gifts -> correct