The answer to this question is most likely A) Protein coat.
To know this, we must know that a virus is a single-celled organism AND classified as prokaryotic (meaning it has no nucleus like Eukaryotic cells do).
A nuclear membrane is a covering that we have around every single eukaryotic cell in our body (also known as a cell membrane), NOT prokaryotic cells.
A tail (or flagellum) is located on the side of some cells in our body and most bacterial cells.
An endospore is a resistant, asexual spore that develops in a bacterial cell.
The only choice that would make even the slightest sense is A) protein coat.
Hope I could help you out! If my answer is incorrect, or I provided an answer you were not looking for, please let me know. However, if my answer is explained well and correct, please consider marking my answer as Brainliest! :)
Have a good one.God bless!
