Decribe systemd and what us servie units and target units?

Systemmd is considered to be the basic building element of the Linux operating system which helps in the controlling and processing of the different program in system .This is majorly used process at the time of the booting up of the Linux system.

Service unit:- when a program/service is to be managed in the Linux system , then this unit comes into action.This unit also has the control over the start of the program as well as stopping of it.Target unit:-is used when there is requirement of changing the level of the system.It also provides the synchronization service to the other units,

The answer is d) all of the above