Defining the limits on free speech in cases of has been very difficult.
a. obscenity
c. artistic expression
b. libel
d. all of the above

The answer is D. all of the above

The limits is really depend on the culture that you're in. In some culture, libeling is punishable by death, meanwhile in another culture it's just a small accusation

In liberal Culture, obscenity and artistic expression is more Tolerable compared to the Area that have a strong Religious culture