Answer:
trojan: manages to hide itself as a system file, for example a trojan could be named after an important file
virus: another name for malware
malware: software that has malicious intent towards your system
botnet: a botnet is a cluster of computers sometimes reffered to as zombies, these computers have been infected with a RAT[Remote Admin Toolkit] (rat is a type of malware that allows remote admin control from another person) these can be used for ddosing services.
Explanation:
