Which of the following represents the correct structure of $\beta-D-(-)-$Fructofuranose?

Consider the following reactions:
$(i)$ $\text{Glucose} + ROH$ $\xrightarrow{\text{dry } HCl} \text{Acetal}$ $\xrightarrow{x \text{ eq. of } (CH_3CO)_2O} \text{acetyl derivative}$
$(ii)$ $\text{Glucose}$ $\xrightarrow{Ni/H_2} A$ $\xrightarrow{y \text{ eq. of } (CH_3CO)_2O} \text{acetyl derivative}$
$(iii)$ $\text{Glucose} \xrightarrow{z \text{ eq. of } (CH_3CO)_2O} \text{acetyl derivative}$
$x, y$ and $z$ in these reactions are respectively:

On hydrolysis,sucrose gives:

Sugar can be tested in urine by

Which of the following pairs of monosaccharides form sucrose?

Which examples of carbohydrates exhibit $\alpha$-link,($\alpha$-glycosidic link) in their structure?