Can someone answer this 3 questions for me in full sentence?

37. what was hitler's "final solution"? a) the construction of walled ghettos in polish cities to hold "undesirable" groups b) a plan to exterminate all jews living in regions controlled by the third reich c) a series of fake medical experiments on jews conducted on topics such as oxygen deprivation d) a plan to force all "undesirable" groups to become "useful members" of the third reich