The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Currently used step back technique is modified, it was given by:   (A) Clam   (B) Wein   (C) Schilder   (D) Mullaney
['(D) Mullaney <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Clam \n (B) Wein \n (C) Schilder \n (D) Mullaney <> possible answers', '  Currently used step back technique is modified, it was given by: <> context@']