How do you explain the presence of an aldehydic group in a glucose molecule ?

Question

$\begin{array}{1 1} \text{(a) Glucose reacts with hydroxide to form a monoxime and adds three molecule of hydrogen cyanide to give cyanhydren .} \\ \text{(b) Glucose reacts with hydroxylamine to form a monoxide and adds two molecule of hydrogen cyanide to give cyanhydren .}\\ \text{ (c) Glucose reacts with hydroxylamine to form a monoxime and adds one molecule of hydrogen cyanide to give cyanhydren.}\\(d)\;\text{None of the above} \end{array}$