If you are asked to classify the various algae into distinct

If you are asked to classify the various algae into distinct groups, which of the following characters you should choose?

1. nature of stored food materials in the cell
2. structural organization of thallus
3. chemical composition of the cell wall
4. types of pigments present in the cell.

It will be types of pigment present in the cell, like Rhodophyceae shows presence of phycoerythrin, chlorophyceae shows presence of phycocyanin etc.