The Difference Between Vertical and Horizontal Transmission of Plant Viruses

The difference between vertical and horizontal transmission of plant viruses is that vertical transmission is ________.

A) transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant
B) the spread of viruses from upper leaves to lower leaves of the plant, and horizontal transmission is the spread of a virus among leaves at the same general level
C) the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size
D) the transfer of DNA from a plant of one species to a plant of a different species, and horizontal transmission is the spread of viruses among plants of the same species