凡图示基坑底面积在20m2以内的为()。
参考答案:基坑
请根据下面的CIDR写法,写出其子网掩码和网络ID()131.107.31.126/28
A.255.255.255.224131.107.31.128
B.255.255.255.240131.107.3.0
C.255.255.255.248131.107.3.64
D.255.255.255.240131.107.3.112