800 defines as a service that is provided by a protocol layer of communicating open systems and that ensures adequate security of the systems or of data transfers

Security service

Explanation:

 X.800 is the security service which is basically provided by the protocol layer of the communication open system. It ensure the proper security system and the data transfer.

Many security system basically implemented various security policies which is implemented by the security mechanism.  The X.800 security service can control the access of the resources and find the particular condition which the access may occur and performed.

There are mainly five types of services which is provided by the X.800 security service that are:

c is the answer for this

answer; the correct answer is (d) binge eating followed by compensatory behavior;