Glucose cannot be classified as which of the following?

Sucrose is

Which of the following pairs gives the same phenyl osazone?

Enumerate the reactions of $D$-glucose which cannot be explained by its open chain structure.

Which of the following pairs is a $C_2$-epimer?

Sugar $X$:
$A.$ is found in honey.
$B.$ is a keto sugar.
$C.$ exists in $\alpha$ and $\beta$-anomeric forms.
$D.$ is laevorotatory.
$X$ is