The idea that viruses originated as genetic material that was able to move within a genome, eventually exiting a cell and entering another is the hypothesis.

Progressive hypothesis

Explanation:

According to this hypothesis, the viruses originate with a progressive process. The mobile of the moving parts of genetic material capable of moving within a genome, gained the ability to withdraw from one cell and enter into another. In other words, viruses have risen from genetic elements that have gained the ability to move between cells .

the answer is d. chordata