单选题：根据下列材料请回答题：Psychologists now believe that noise hasa conside

根据下列材料请回答题：Psychologists now believe that noise hasa considerable effect on people’s attitudes and behaviors. Experiments have proved that in noisysituations (even temporary ones), people behave 67 cooperatively and more irritably; in more 68 noisy situations, many people cannot 69 theirattention on the work, and they suffer from severeanxiety as 70 as other psychological problems. 71, psychologists distinguish betweensound and noise. Sound is measured 72indecibels (分贝). Noise cannot be measured in thesame 73 because it refers to the psychologicaleffect of sound and its level of 74 dependson the situation.75 , for passengers at anairport who expect to hear airplanes taking offand landing, there may be a lot of sound, butnot much noise (that is, they are not 76 bythe noise). By 77, if you are at a concert andtwo people behind you are 78 , you feel theyare talking noisily even if there is not much79 . You notice the noise because it 80 youpsychologically.
Both sound and noise can have 81 effects,but what is most important is if the person hascontrol 82 the sound or not. People walkingdown the street with earphones, listening tomusic that they enjoy, are receiving a lot ofdecibels of sound, 83 they are probably happyhearing sounds which they control. On the 84hand, people in the street without earphones must 85 a lot of noise which is beyond their control. It is noise pollution 86 we need to control in orderto help people live more happily.填入（67）处最佳答案是（ ）。 A．better
B．less
C．more
D．worse