The correct answer is C. Indispensible. The correct spelling is indispensable.
A. Prejudicial is an adjective that means harmful or damaging to someone's reputation or interests. B. Affectionate is an adjective that means showing or feeling love or fondness. D. Assiduous is an adjective that means showing great care and effort.
The word indispensable is often misspelled as indispensible. This is because the prefix in- can sometimes be used to mean not or without. However, in the word indispensable, the prefix in- does not have this meaning. Instead, it means essential or necessary. Therefore, the correct spelling of the word is indispensable.