Answer : The correct option is, (b) hydroxyl group.
Explanation :
Glucose is a monosaccharide sugar and it is the most important carbohydrates. It is used as the source of energy in both animals and plants. Glucose is the main products in the photosynthesis.
Sugar glucose is an organic compound which composed of the elements carbon, hydrogen and oxygen. The functional groups present in the sugar glucose are hydroxyl, aldehyde groups.
From the given options, only hydroxyl group allows the sugar glucose to dissolve in blood.
Hence, the correct option is, (b) hydroxyl group.
The structure of the glucose is shown below.