Which of the following is a complex sentence?
a. Check out the editorial page in today''s paper and you''ll notice the piece by Oscar Lewis.
b. I would like to visit the Kinshasa, but I understand the city is unsafe for foreigners.
c. As Jake was reading the letter from June yet again, the flight attendant coughed gently to get his attention.
d. I simply cannot make heads or tails of rap lyrics, but I suppose I''m just too old to understand them.