This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Carbohydrates, Subject name: Biochemistry
Which test is given positive by Glyceraldehyde? 
Select and explain. 
A. Benedicts test, B. Molisch's test, C. Seliwanoff's test, D. Gerhard's test
A: Benedicts test
Answer: A: Benedicts test 
Explanation: Ans. A. Benedicts testGlyceraldehyde is a monosaccharide. All monosaccharides are reducing sugars. All reducing sugars gives positive Benedict's test.Molisch's test is a general test for all the carbohydrate but it is positive if number of carbons are 5 or more. Glyceraldehyde contains only 3 carbons.Seliwanoff's test is positive for keto sugars. Glyceraldehyde is an aldehyde.Gerhard's test & Rothera's test are positive for ketone bodies.