When Two Organ Pipes Open at Both Ends Sound a Perfect

Multiple Choice

When two organ pipes open at both ends sound a perfect fifth, such as two notes with fundamental frequencies at 440 Hz and 660 Hz, both pipes produce overtones. Which choice below correctly describes overtones present in both pipes?

A) 440, 880 and 1 320 Hz.
B) 660, 1 320 and 1 980 Hz.
C) 880, 1 320 and 1 760 Hz.
D) 1 320, 2 640 and 3 960 Hz.
E) They have no overtones in common.