单项选择题

A.Create two SRV records.Assign the SRV record for Server1 a priority of 20.Assign the SRV record Server2 a priority of 10.
B.Create two SRV records.Assign the SRV record for Server1 a priority of 10.Assign the SRV record for Server2 a priority of 20.
C.Create two MX records.Assign the MX record for Server1 a priority of 20.Assign the MX record for Server2 a priority of 10.
D.Create two MX records.Assign the MX record for Server1 a priority of 10.Assign the MX record for Server2 a priority of 20.