It depends how many points you have total in the class.
The correct answer would be the word melancholy. Conceited and humble are of opposite meaning or antonyms. Jubilant means of extreme happiness or triumph. Therefore, the word that would complete the analogy should be opposite to the meaning of the word jubilant, which is "melancholy".
Parallelism and antithesis helps to not only help the speech flow, but to reinforce certain key ideas and points
20 - 10 = 10
your answer is 10
hope this helps