The answer can be
however
(Mandy practiced karate everyday, however, she failed to beat her final opponent)
Tybalt is Juliet's cousin, originally, Tybalt wanted to duel Romeo instead. But since he and Juliet are married, he cannot fight Tybalt as he is basically his cousin-in-law, thus, Romeo rejects Tybalt's challenge. Mercutio finds this quite cowardly as a result he himself challenges Tybalt to fight.
D. Mary’s life did not turn out well (110% the right answer)
