What is the main purpose of the text?

To describe the benefits of creating an observation unit in emergency services.
To explain the different types of observation units in emergency services.
To discuss the challenges of managing emergency services.
To provide a history of the development of emergency services.
a) I and II are correct.
b) II and III are correct.
c) I only is correct.
d) III only is correct.
e) I and III are correct.