The correct answer is A. sentimental.
Sentimental is an adjective that means “characterized by or given to excessive emotionality.” It is often used to describe someone who is easily moved to tears or who expresses their emotions in a very dramatic way.
Mawkish is an adjective that means “excessively sentimental or emotional.” It is often used to describe something that is so sentimental that it is almost embarrassing.
The other options are not antonyms of mawkish.
B. Intelligent is an adjective that means “having or showing a high or quick intelligence.” It is not the opposite of mawkish because someone can be intelligent and sentimental at the same time.
C. Certain is an adjective that means “having or showing complete certainty or assurance.” It is not the opposite of mawkish because someone can be certain and sentimental at the same time.
D. Carefree is an adjective that means “free from anxiety or worry.” It is not the opposite of mawkish because someone can be carefree and sentimental at the same time.