In aqueous solution, glucose remains as-

Options

A. only in open chain form
B. only in pyranose form
C. only in furanose form
D. in all three forms in equilibrium

Answer

D

Explanation

The six-membered cyclic form is generally reffered to as the 'pyranose' form, and the five-membered cyclic form is called the 'furanose' form.
Closure of the ring creates a chiral center at `C-1` resulting in two diastereomers (sometime called ''anomers'') the alpha `(alpha)` and beta `(beta)` forms