Answer :
Since a pun can be referred to as "word play", comma sense is what correctly explains the pun.
Answer:
The sentence that correctly explains the pun in the sentence and the words on which it is built is the following one: Comma sense- a play on the phrase common sense.
Explanation:
The sentence above is talking about an English teacher, a person who has studied grammar and teaches it for a living. What is more, the person describing this teacher is saying that she is practical. That is why she has a lot of common sense. Therefore, the pun lies on the spelling of this phrase, "common sense", because instead of writing "common", the writer used "comma", which has a similar pronounciation. Besides, a punctuation mark such as a comma is part of the scope of study of an English teacher.