70% of the people who see doctors of any kind for lower back problems report some improvement within 90 days. [Some see doctors who manipulate their spine, others get drug treatments, and some undergo surgery.] 70% of the people who do not seek medical help report that their lower back problems come and go; get worse, and then better for no discernable reason.
What conclusions do the above facts support? (a) the cure for lower back pain in known (b) the cure for lower back pain is unknown (c) the cause of lower back pain is unknown (d) the cause of lower back pain is known