C
B
70 dB
B
B
71 dB
B
A
C
B
B
A
7 dB
C
B
69 dB
C
A
7 dB
C
C
69 dB
B
B
71 dB
D
C
69 dB
B
A
71 dB
C
B
B
C
B
68 dB