How many secondary hydroxyl groups are present in glucose?

The fructose molecule in sucrose exists as:

Which of the following does not contain a hydrophobic structure?

The correct statement$(s)$ about the following sugars $X$ and $Y$ is(are):
$(A)$ $X$ is a reducing sugar and $Y$ is a non-reducing sugar
$(B)$ $X$ is a non-reducing sugar and $Y$ is a reducing sugar
$(C)$ The glycosidic linkages in $X$ and $Y$ are $\alpha$ and $\beta$,respectively
$(D)$ The glycosidic linkages in $X$ and $Y$ are $\beta$ and $\alpha$,respectively

Match List-$I$ with List-$II$:

List-$I$ $(\text{Saccharides})$	List-$II$ $(\text{Glycosidic linkages found})$
$(A)$ Sucrose	$(I)$ $\alpha 1-4$
$(B)$ Maltose	$(II)$ $\alpha 1-4$ and $\alpha 1-6$
$(C)$ Lactose	$(III)$ $\alpha 1-\beta 2$
$(D)$ Amylopectin	$(IV)$ $\beta 1-4$

Choose the correct answer from the options given below:

For osazone formation,the effective structural unit necessary is: