Food reserve in Rhodophyta is:
Floridean starch
Mannitol
Leucosin
All of the above
Red algae store sugars as floridean starch.
The reserve food of brown algae is laminarin and Mannitol.
"Leucosin" is part of carbohydrate which stores the food in yellow green algae. This yellow green algae is of Chrysophyceae class.
Green algae have starch as the food reserve.