There is a circular lawn with an area of 700 square meters, and it is planned to install an automatic rotary sprinkler for irrigation. There are three types of devices with a range of 20 meters, 15 meters and 10 meters. Which do you think is the most suitable choice?
有一个面积为700平方米的圆形草坪，准备为它安装自动旋转喷灌装置进行喷灌，现有射程为20米、15米和10米的三种装置．你认为应选哪种最合适？
<result>15</result>