The reaction of glucose with methyl alcohol in the presence of dry HCl shows that it is a:

Cyclic hemiacetal

The correct answer is option 1. Cyclic hemiacetal.

The reaction of glucose with methyl alcohol in the presence of dry HCl shows that it is a cyclic hemiacetal.

A hemiacetal is a compound that contains both an aldehyde and an alcohol group on the same carbon atom. Glucose has an aldehyde group at the end of the molecule, and it also has several hydroxyl groups. When glucose reacts with methyl alcohol in the presence of dry HCl, the aldehyde group reacts with the methyl alcohol to form a hemiacetal.

The other options are incorrect. A polyhydroxy ketone is a compound that contains multiple hydroxyl groups and one ketone group. A polyhydroxy alcohol is a compound that contains multiple hydroxyl groups and no ketone or aldehyde groups. A polyhydroxy aldehyde is a compound that contains multiple hydroxyl groups and one aldehyde group.