Which of the following is a compound-complex sentence? a. My mother and my sister are on opposite sides of the controversy, but I have chosen to say out of it.

b. Although my father is not an activist; I have become involved in the GMO controversy, but I remain respectful of my father's opinion.

c. Unlike my mother, I don't care to get involved in the GMO controversy.

d. My mother is not in favor of mandatory labeling, but my sister supports mandatory labeling.