Within the realm of IT security, which of the following combinations best defines risk?

A.
Threat coupled with a breach.

B.
Threat coupled with a vulnerability.

C.
Vulnerability coupled with an attack.

D.
Threat coupled with a breach of security.

Explanation:
This is the main concept, when we talk about a possible risk we always have a
possible vulnerability in the system attacked. This vulnerability can make a threat to be successful.
We can say that the level of risk can be measures through the level of vulnerabilities in our current
systems and the ability of the attackers to exploit them to make a threat successful.