What are two things that are possible when scanning UDP ports?

What are two things that are possible when scanning UDP ports? (Choose two.

A.
A reset will be returned

B.
An ICMP message will be returned

C.
The four-way handshake will not be completed

D.
An RFC 1294 message will be returned

E.
Nothing

Explanation:
Closed UDP ports can return an ICMP type 3 code 3 message. No response can mean the port is open or the packet was silently dropped.