The correct option is C glimpse
Option C: 'Glimpse' means 'a momentary or partial view'. Here, it refers to the 'partial view of him in the crowd for a fleeting moment'. Hence this word is suitable for this sentence; and option C is correct.
Option A: 'Glare' means 'to stare in an angry or fierce way'. The person does not display an angry emotion, and one cannot 'stare' for "a fleeting moment".
Hence option A is incorrect.
Option B: 'Glance' means 'to take a brief and hurried look'. The difference between 'glance' and 'glimpse' is that you intentionally glance at someone for a short moment. But, a glimpse is when you by chance look at something without intending to.
For this sentence, 'the person 'caught' a glimpse, it means 'by chance' and did not intend to.
(Also, 'caught a glimpse' is a set expression, and 'stole a glance' is another set expression.)
Hence option B is incorrect.
Option D: 'Look' means 'to turn our eyes in a direction to see something'.
This word, too, does not provide the required meaning.
Hence D is incorrect.