Among followings, _ enzyme is naturally found in human immunodeficiency virus (HIV).

Explanation

HIV is a retrovirus. Its genome consists of RNA molecules, and it possesses a 'reverse transcriptase enzyme', which allows the virus to use its RNA as a template to construct copies of DNA, which it uses to incorporate into the genome of the host cell. The remaining enzymes (ligase, RNA, and DNA polymerase) are present in the host cell, which HIV uses for its own proliferation upon infecting the cell. Hence, the correct option is B.