The correct option is
A (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
Spirogyra is a filamentous charophyte green alga of the order Zygnematales. Named for their beautiful spiral chloroplasts, within thin unbranched chains of cylindrical cells.
Chlamydomonas is a genus of green algae consisting of unicellular flagellates, found in stagnant water and on damp soil, in freshwater, seawater, and even in snow as "snow algae".
Volvox is a genus of chlorophyte green algae in the family Volvocaceae. It forms spherical colonies of up to 50,000 cells.
Giant bladder kelp (M. pyrifera) is the largest alga species, measuring up to 65 metres (215 feet) long.