The following are multiple choice questions (with answers) about medical knowledge.   **Question:** What type of fibers are principal fibers of the PDL?   (A) Elastic   (B) Reticular   (C) Collagenous   (D) Collagenous and elastic
['(C) Collagenous <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Elastic \n (B) Reticular \n (C) Collagenous \n (D) Collagenous and elastic <> possible answers', '  What type of fibers are principal fibers of the PDL? <> context@']