Perform some research on Advanced Persistent Treat $38$ group and answer the following questions:

a$)$ How is the suspected source of the group $($usually a country$)?$

b$)$ What are the targets of the group?

c$)$ How large is the group believed to be$?$

d$)$ What has the group been able to achieve?

e$)$ How long has the group believed to have been active?

f$)$ What kind of infrastructure did they use?