The quarrel between Olu and Ola will end up … a fight.

Analyze the question: We need the correct preposition to follow the phrasal verb "end up" when the next word is "a fight."

Explain the concept: In English, certain verbs and phrases take fixed prepositions. "End up in" is the usual collocation when the result is a situation, state, or event. For example:

• He ended up in jail.
• The argument ended up in a fight.
• They ended up in trouble.

"End up with" is normally followed by something a person acquires or possesses, such as "She ended up with a prize." "End up by" is followed by an -ing form, such as "He ended up by shouting at everyone."

Solution:

• A. by a fight: wrong, because "by" would need a gerund (ended up by fighting).
• B. in a fight: correct, because it is the natural collocation for a result or outcome (a quarrel ending in a fight).
• C. with a fight: this is sometimes heard, but it is not the standard idiom for this meaning in exam English.
• D. among a fight: wrong, because "among" is used with groups of three or more people or things and doesn't fit here.

Answer: B. in

Tip: Remember the pattern "end in" + result/event (end in tears, end in a fight, end in disaster). Also keep "among" for groups of three or more, and "between" for two people, as in "between Olu and Ola."