The following are multiple choice questions (with answers) about medical knowledge.   **Question:** In a child with tetralogy of Fallot with fever and diarrhea, which of the following is the surest sign of a cyanotic spell?   (A) Hepatomegaly   (B) Absence of murmur   (C) S3 gallop rhythm   (D) Aerial oxygen saturation of less than 75%
['(B) Absence of murmur <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Hepatomegaly \n (B) Absence of murmur \n (C) S3 gallop rhythm \n (D) Aerial oxygen saturation of less than 75% <> possible answers', '  In a child with tetralogy of Fallot with fever and diarrhea, which of the following is the surest sign of a cyanotic spell? <> context@']