The evolution of multicellularity in eukaryotes A. occurred independently in several eukaryotic lineages B. occurred only once, in the common ancestor of all eukaryotes C. occurred only once, in the common ancestor of all animals D. occurred only once, in the common ancestor of all multicellular eukaryotes

A) occurred independently in several eukaryotic lineages

Explanation:

The primitive organism which evolved from the larger molecules were the prokaryotes mainly bacteria. Later these bacteria formed an endosymbiotic relationship with each other and formed proto-eukaryotes. These proto eukaryotes formed the eukaryotic around 2 billion years ago.

However, the eukaryotes were formed once in the history of the evolution of organism but these eukaryotes later formed the symbiotic relationship which diverged into the plants and the animals. In these lineages, the multicellularity appeared many times that is more than once.

Thus, Option-A is correct.