Answer:
b) White-hat hacker
Explanation:
This is also called an ethical hacker. Unlike the other options, a white-hat hacker is a person specialized on computational security which offers services to organizations to test how safe they are from informatic attacks (viruses, theft of information, etc). This is carried out based on a agreement between the whihte-hat hacker and the client via a contract.
No, I believe it is "You should use proper grammar when asking a question".
Answer:
noise because it is a random interference that obscures a signal.