Why Is Tertiary Syphilis Difficult to Treat

Why is tertiary syphilis difficult to treat?

A) The bacteria are no longer actively multiplying, and antibiotics work against dividing cells.
B) The bacteria have moved into deep tissues that are not accessible by medications.
C) The bacteria have migrated to the brain, which is protected by the blood-brain barrier.
D) The bacteria have formed biofilms, which protect them from the effects of antibiotics.
E) The bacteria have formed endospores, which are resistant to the effects of antibiotics.