Which one of the following systems of plant classification is not phylogenetic?

The correct option is C Bentham and Hooker's system
The phylogenetic relationship is defined as the relationship between the plant and its ancestors. Bentham and Hooker's system of classification is based on the seed plants and the classification does not depend on phylogenetic relations with their ancestors. The other three classifications involve phylogenetic relationships. Hence, the correct answer is option A.