which port does a Cisco IOS IP SLA source use to send a control message to an IP SLA responder?

To initiate testing, which port does a Cisco IOS IP SLA source use to send a control message to an IP SLA responder?
Select the best response.

A.
UDP port 2020

B.
UDP port 1967

C.
TCP port 2020

D.
ICMP port 1967