Answer:
The best evidence that a cell is eukaryotic is the presence of the cell structure called the nucleus.
Step-by-step explanation:
The most significant difference between eukaryotic and prokaryotic cells is that the former have a nucleus, where they store genetic information in the form of DNA.
The nucleus of eukaryotic cells occupies approximately the center of the cell and is a structure associated with the endomembrane system. Its function is to control cell activity, and its genetic material is duplicated before cell division.
In prokaryotic cells, in the absence of a nucleus, the genetic material is dispersed in the cellular cytoplasm.
Regarding the other options:
Both cell types, eukaryotes and prokaryotes, have ribosomes, genetic material and cell membrane.