Choose the most suitable option to replace the highlighted part of the sentence:
I am confident to pass the examination.

Correct option is C

The correct substitution of the highlighted words is (c) of passing the examination.
Explanation:
The adjective “confident” is correctly followed by the preposition “of” when we refer to being sure about doing something.
Hence, the correct structure is confident of + V-ing / noun.
The phrase “confident to pass” is considered non-standard in formal grammar for exams.
Therefore, replacing it with “confident of passing” makes the sentence grammatically correct and natural.
Grammatical rule used:
confident of + V-ing / noun
Example: She is confident of winning the competition.
Information booster / exceptions related to the topic:
We can also say confident that + clause: I am confident that I will pass the examination.
But with an action (verb), prefer of + V-ing.