Explanation
Correct answer: C.
Choice C is the best answer. The convention being tested is end-of-sentence punctuation. This choice correctly uses a question mark to punctuate the interrogative sentence "where did the word ‘chortle’ come from," which asks a direct question.
Why the other choices are wrong
Choice A
Choice A is incorrect because a period can’t be used in this way to punctuate an interrogative sentence, such as "where did the word ‘chortle’ come from."
Choice B
Choice B is incorrect because "where the word ‘chortle’ did come from" does not follow the conventional structure of a direct question in Standard English. It’s conventional in Standard English to follow the interrogative word "where" with an auxiliary verb (such as "did") when asking a direct question.
Choice D
Choice D is incorrect because "where the word ‘chortle’ come from" does not follow the conventional structure of a direct question in Standard English. It’s conventional in Standard English to follow the interrogative word "where" with an auxiliary verb (such as "did") when asking a direct question. Furthermore, a period can’t be used in this way to punctuate an interrogative sentence.