Which statement about the IP SLAs ICMP Echo operation is true?

Which statement about the IP SLAs ICMP Echo operation is true?
A . The frequency of the operation. s specified in milliseconds.
B . It is used to identify the best source interface from which to send traffic.
C . It is used to identify the best source interface from which to send traffic.
D . It is used to determine the frequency of ICMP packets.

Answer: D