What policy, provide by a typical ISP, should be read and understood before performing any port scanning outside of your private network?

acceptable use policy (AUP)

Explanation:

Based on the information provided within the question it can be said that the type of policy that this statement is referring to is an acceptable use policy (AUP). This is a policy that states all the rules that have been applied by the owner, creator or administrator of a network or service, explaining what is allowed and how the network should be used.

i think its c but i'm not