Which of the following statements regarding pelvic inflammatory disease (PID) is correct?
a. The most severe cases of PID occur in women who are not sexually active.
b. PID can scar the fallopian tubes, which increases the risk of an ectopic pregnancy.
c. PID most commonly affects women who have had an ectopic pregnancy in the past.
d. The most common presenting symptom of PID is generalized upper abdominal pain.