The correct answer is Option D.
SALUBRIOUS means healthy and health giving. The antonym of the word will be the word which means the opposite to this meaning.
MALAISE means a general feeling of discomfort and illness. This is opposite to healthy.
Thus MALAISE is the correct answer.
The remaining options are incorrect because:
STICKY means something that tends to stick.
SOFT means something that is easy to mould and compress.
FAMOUS means well-known.
These are not opposite to healthy.