The correct option is D A-iv, B-iii, C-ii, D-i
Algae occur in a variety of habitats like aquatic, moist areas and even in association with fungi known as lichens.
The form and size of algae is highly variable. The size ranges from the microscopic unicellular forms like Chlamydomonas, to colonial forms like Volvox and to the filamentous forms like Ulothrix.