Which of these is a compound sentence? (pls leave an explanation if possible)

A. Lucy and Richmond heard about work in California.
B. They could buy some land and a house in California´s Central Valley.
C. Folks were struggling to survive in most places, but in California they had jobs.
D. Lucy and Richmond packed up, hopped on a train, and went west.

C.

Explanation:

I believe it's C because in this sentence, it talks about how they were struggling in one place, and then in the sentence they added that California had jobs. Therefore, I believe it's C but let me know in the comments if I'm wrong!

in "letter from a birmingham jail," king argues that there are four basic steps in any nonviolent campaign: "[c]ollection of the facts to determine whether injustices exist; negotiation; self purification; and direct action." finally, direct action is taken and acts such as boycotts and sit-ins are staged.

answer; (d) i believe the best answer is ; ///people said that man could not fly, but in 1903, orville and wilbur wright made the first sustained powered flight in a heavier- than-air machine;