Find the word that names a necessary part of the underlined word.
1.  ovation
A. outburst
B. bravo
C. applause
D. encore

2.  bonus
A. reward
B. raise
C. cash
D. employer

3.  antique
A. rarity
B. artifact
C. aged
D. prehistoric

4.  culture
A. civility
B. education
C. agriculture
D. customs

5.  knowledge
A. school
B. teacher
C. textbook
D. learning