A is malware that copies itself repeatedly, using up system resources and slowing a system or device until it hangs and no longer functions.

worm

Explanation:

A computer worm is a type of malware that spreads copies of itself from computer to computer. A worm can replicate itself without any human interaction, and it does not need to attach itself to a software program in order to cause damage.

answer; i believe the correct answer is layers;

i think the answer is a or d