A DNS server has MX records which indicate that there are three SMTP relays for the domain gvon.com. A problem occurs, whereby other DNS servers make iterative queries for the MX records every time they are queried by clients. Which two MX lines cause remote DNS servers to refuse to cache the MX record for SMTP relay smtp.gvon.com? (Choose two.)

A.
gvon.com. 0 in mx 0 smtp.gvon.com.

B.
gvon.com. in mx 5 smtp.gvon.com.

C.
gvon.com. 0 in mx 5 smtp.gvon.com.

D.
gvon.com. 100 in mx 10 smtp.gvon.com.

E.
gvon.com. mx 100 smtp.gvon.com.