The correct answer is C. They reproduce more slow than unicellular organisms.
Multicellular organisms are termed as organisms which consists of more than one cell. A good example of multicellular includes plants, land, and animals.
Multicellular arises in different ways for example, aggregation of many single cells or cell division.
They evolved in six eukaryotic groups which include green algae, red algae, brown algae, animals, and fungi.