Four different phylogenetic trees of a group of salamanders have been proposed. Trees A and B each require 19 homoplasies, but tree A requires 16 synapomorphies, and tree B requires 15 synapomorphies. Tree C requires 15 homoplasies and 18 synapomorphies. Finally, tree D requires 22 homoplasies and 9 synapomorphies. According to the principle of parsimony, which tree or trees is/are the best?