Which sentence uses commas correctly to set off a nonrestrictive clause?
A. There are very few large cities in Wyoming which is a state known
for having a small population.
B. Chicago, which is the largest city in Illinois, is famous for being
windy.
C. Washington D.C., which became the U.S. capital in 1790 is not
actually a state.
D. Towns named Springfield which is a very popular name, can be
found in 34 states.