Which of the following pairs of monosaccharides form sucrose?

Two forms of $D$-glucopyranose are obtained from the solution of $D$-glucose. What are these called?

The given structure is the enol form of:

Which of the following pairs will give the 'Tollens' test'?

Name the macromolecules that are chosen as drug targets.

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?