Answer:
The correct answer is letter "B": Between the Operating system and the utilities.
Explanation:
Rootkits are malicious software such as Trojans, worms or viruses themselves that allow unauthorized users to have access to a computer typically hidden from the scope of the user, using for that purpose another frequent application. Sensitive information like bank credentials can be easily obtained through this type of software. Rootkits are stored between the computer's Operating System (OS) and its utilities like most viruses.