which among the following would be appropriate?

Exhibit Study the log given in the exhibit, Precautionary measures to prevent this attack would include writing firewall rules. Of these firewall rules, which among the following would be appropriate?

A.
Disallow UDP 53 in from outside to DNS server

B.
Allow UDP 53 in from DNS server to outside

C.
Disallow TCP 53 in form secondaries or ISP server to DNS server

D.
Block all UDP traffic