Despite the recent setbacks, her ____________ outlook on the future remained unshaken, always expecting the best outcome.
Correct: C
The sentence describes an outlook that remains unshaken despite setbacks and always expects the best outcome, indicating optimism. 'Sanguine' means optimistic or positive, especially in an apparently difficult situation. This fits perfectly. 'Lugubrious' means looking or sounding sad and dismal. 'Despondent' means in low spirits from loss of hope or courage. 'Cynical' means believing that people are motivated by self-interest; distrustful of human sincerity or integrity. These are all antonyms or inappropriate for the context.