Which of the following pairs is of unicellular algae?

Chlorella and Spirulina are unicellular algae that are rich in proteins and are used as food supplements even by space travellers.$\text{Gelidium}$ and $\text{Gracilaria}$ are multicellular red algae.$\text{Laminaria}$ and $\text{Sargassum}$ are multicellular brown algae.