Concept: A computer virus is a harmful, self-replicating program that hides inside a system.
It copies itself into memory and storage in order to spread.
Explanation: The question describes a self-contained code that tries to stay undetected.
This code copies itself into computer memory and then into the hard disk.
These are the exact characteristics of a computer virus.
A virus often interferes with the operating system and may corrupt programs and data files.
Hardware refers to physical parts of the computer, so option A is not correct.
Software is a general term for programs, but not all software is harmful or self-copying, so option B is not correct.
Computer remedies are repair tools or solutions, not a spreading malicious code, so option C is not correct.
Therefore, the correct answer is the virus.
Answer: D. Virus