The RARP protocol sends out a packet, which includes its MAC address and a request to be informed of the IP address that should be assigned to that MAC address.
ARP does the opposite by broadcasting a request to find the Ethernet address that matches a known IP address.
ICMP supports packets containing error, control, and informational messages (e.g. PING).
UDP runs over IP and is used primarily for broadcasting messages over a network.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the
Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87.

The correct answer is "Key clustering" Answer "Public key cryptography" describes a type of cryptographic system using a public and a private key; answer Cryptanalysis is the art/science of breaking ciphers; answer Hashing is the conversion of a message of variable length into a fixed-length message digest.

The correct answer is: The subject's sensitivity label must dominate the object's sensitivity label.
With a Multi-level security policy you have information that has different sensitivity labels. In order to read an object the subject's sensitivity label must be equal to or greater than that of the object. So it would be considered to dominate it, no read up.
The following answers are incorrect: The subject's sensitivity label subordinates the object's sensitivity label. Is incorrect because if the subject's sensitivity label subordinates the object's sensitivity label that would mean it is lower and the subject should not have read access to the object.
The subject's sensitivity label is subordinated by the object's sensitivity label. Is incorrect because the this would not allow for read access if the sensitivity lables were equal. So the subject's sensitivity label is not subordinated by the object's sensitivity label, the subject's label must dominate the object's label. Remember dominate means equal to or greater than where subordinate means less than.
The subject's sensitivity label is dominated by the object's sensitivity label. Is incorrect because if the object's sensitivity label dominates the subject's sensitivity label then the subject should not have access, it is the subject that must dominate the object and not the other way around. Remember dominate means equal to or greater than so this would mean that the object's sensitivity label is equal to or greater than the subject.
According to the OIG, Multi-level security is defined as a class of system-containing information with different sensitivities that simultaneously permits access by users with different security clearances and need-to-know, but prevents users from obtaining access to information for which they lack authorization. The Subject's sensitivity label must be equal to or greater than the object's sensitivity label in order for the subject to have read access to it, no read up.