Directions: The following question contains three sentences labelled as A, B, and C, each with a highlighted word. Identify the word from the given options that is the antonym of all three highlighted words.

A: Despite the discouraging milieu, many scientists continue to strive for excellence in their work.

B: The initial response to the research proposal was quite disheartening.

C: Facing a demoralizing situation, the team tried to keep their spirits high.