Select the most appropriate option to substitute the highlighted segment in the given sentence.
It is ironical that the students had to be punished because of a report submitted by a teacher who himself was not above suspicion.

Correct option is C

The most appropriate option to substitute the highlighted segment in the given sentence is: (c) No substitution required
The original sentence uses "ironical" correctly, which is an adjective form meaning "characterized by irony."
While "irony" (noun) and "ironically" (adverb) are also correct words, they would not fit grammatically in this context without restructuring the sentence.
Others Options:
· "Irony" (option b) is incorrect—the correct noun form is "irony," but the sentence requires an adjective here.
· "Ironicism" (option a) is not a standard English word.
· "Ironically" (option d) is an adverb and would require rephrasing (e.g., "Ironically, the students had to be punished...").
Thus, the original phrasing is correct, and  no substitution is required.