B, so that the residents of residential buildings are wearing an anti-noise earmuffs can attenuate the noise, but does not apply to the actual situation, so B is wrong;
C, the installation of noise monitoring devices in residential buildings can not attenuate the noise, so C is wrong;
D, the huge noise is mainly because of the loudness of the sound it sends out, so when dancing in the square dance to make the big moms to lower the pitch of the sound can not be reduced. The pitch of the sound can not attenuate the noise, so D error.
Therefore choose A.