The correct answer is Option 4: No Article

The sentence would read: "Ms. Anita wishes to join you today for the event." 

Titles such as Mr., Mrs., Ms., Dr. used before proper names generally do not take an article.

Note: The given answer is as per the NTA Answer Key. However, grammatically, Option 1 (“A”) can also be considered acceptable in a different context. In English, the structure “A + proper noun/title” is sometimes used to refer to an unfamiliar or unspecified person. Thus, the sentence:

“A Ms. Anita wishes to join you today for the event” would mean “a certain person named Ms. Anita” or “someone called Ms. Anita,” usually when the speaker or listener does not personally know the person being referred to.