What Is a Denial of Service Attack

Multiple Choice

What is a denial of service attack?

A) It is an attack when the perpetrator is inserting malicious query in input such that it is passed to and executed by an application program.
B) It is an attack when the perpetrator is inputting so much data that the input buffer overflows.The overflow contains code that takes control of the company's computer.
C) It is an attack when the perpetrator uses software to guess company's addresses,send employees blank e-mails,and add unreturned messages to spammer e-mail list.
D) It is an attacked when the perpetrator sends hundreds of messages from randomly generated false addresses,overloading an Internet service provider's e-mail server.