Institution: Bangladesh Public Service Commission (BPSC) Exam: 17th BCS Preliminary Exam 1996
Topic: Spelling, Subject: English Grammar (ইংরেজি গ্রামার)

Best Answer Explained in Below-:

The correct spelling is "humorous" (option C) because this is the officially accepted and standard way to spell the adjective that describes something that is funny or capable of inducing laughter. The word derives from the Latin "humor," meaning fluid or liquid, which later evolved to denote emotional states.

The other options have spelling errors or are not recognized forms. "Humourous" (A) includes an unnecessary "u," confusing it with the British English spelling of "humor," which remains incorrect as an adjective in this case. "Humourious" (B) is a misspelling, as it incorrectly adds an additional "u" and does not conform to standard English spelling conventions. Finally, "humorious" (D) is also incorrect, as it modifies the original root inappropriately and lacks a widely accepted definition.

In summary, "humorous" is the accurate term, used in both American and British English, to describe something that provokes laughter, making it the only correct choice among the given options.