Which of the following is a compound-complex sentence?
a.
Although my father is not an activist, I have become involved in the GMO controversy, but I remain respectful of my father's position.
b.
My mother is not in favor of mandatory labeling, but my sister supports mandatory labeling.
c.
My mother and my sister are on opposite sides of the controversy, but I have chosen to stay out of it.
d.
Unlike my mother, I don't care to get involved in the GMO controversy.