Which of the following statements is $CORRECT$ about saccharic acid?

Maltose contains how many oxygen atoms?

Name the sugar present in milk. How many monosaccharide units are present in it? What are such oligosaccharides called?

Which of the following sugars is the sweetest?

Four carbohydrates: glucose,lactose,sucrose,and starch are present. Different tests are carried out with these $4$ carbohydrates separately. The following observations are made:
$(a)$ Heated: It is charred.
$(b)$ $I_2$ solution: No violet colour.
$(c)$ Fehling solution: Reddish brown precipitate is observed.
$(d)$ It does not reduce copper$(II)$ acetate to $Cu_2O$. No red precipitate is observed in $5 \ min$.
Which carbohydrate satisfies all the above observations?

Write a general note on carbohydrates. Give the classification of carbohydrates.