Which pathogen depends on living cells to reproduce

The correct answer is viruses.

Explanation:

A virus is the pathogenic non-living organisms which infect the host.

They are considered non-living as they do not have their own replication machinery and so depend on the host for their replication machinery, therefore, they are non-living without host organisms and need a host to survive.

Virus inject their genetic material in the host where it is integrated into the DNA of the host and the segment of the DNA of the virus gets replicated along with the DNA of the host which is then coated with the capsid of the virus,

Thus, the virus is the correct answer.