Select the most appropriate adjective to fill in the blank. My friend has a…

"Former" and "latter" are a correlative pair of pronoun-adjectives used to refer back to exactly two people or things already named in a sentence, without repeating their names. "Former" points to the first-named of the two; "latter" points to the second-named of the two. The pair applies only when precisely two items have been introduced, never three or more.

This sentence introduces two people — "a son and a daughter." It already uses "the former" for the first-named person (the son, who is an engineer). The blank needs the word that refers to the second-named person (the daughter, who is the CEO). The correlative word for "the second of two already-named items" is "latter", so the blank is completed with "latter".

Comparing the other options by their own meaning:

• "Late" describes something happening after the expected time, or refers to a person who has died — it is not a correlative reference to a previously named person.

• "Later" is the comparative form of "late", placing one point in time after another (for example, "meet later") — it does not point back to the second of two already-named people.

• "Latest" is the superlative form of "late", denoting the greatest recency in a time sequence (for example, "the latest model"); it expresses timing, not a correlative reference to the second of two already-named people.

Since the sentence needs a correlative counterpart to "former" that refers to exactly the second of the two people named, "latter" is the grammatically correct word for the blank.