Refer to the Figure

Refer to the figure. The organism shown is thought to be similar in form to the ancestor of the Plantae.With this in mind, which description best summarizes the ancestor of plants?

A) Primary endosymbiosis by a multicellular eukaryote resulted in the engulfment of a photosynthetic bacterium that over time became the chloroplast.
B) Primary endosymbiosis by a unicellular eukaryote resulted in the engulfment of a photosynthetic bacterium that over time became the chloroplast.
C) Plant ancestors contained two chloroplasts.
D) Plants evolved from a photosynthetic bacterium.
E) Endosymbiosis of a chloroplast by a nonphotosynthetic bacterium produced the ancestor of plants.