This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'Contraindication of using a bar type direct retainer is: \nSelect and explain. \nA. Used on a distobuccal on terminal abutments, B. When aesthetics demand less display of metal, C. When a push type of retention is needed, D. When a large tissue undercut is present', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Gingivally approaching clasps (e.g. bar clasp) is contraindicated in severe soft tissue (gingival) undercut.\nIn such cases, occlusally approaching clasp configurations are more suitable.', 'role': 'assistant'}]