All Things Being Equal, Which of These Is the Most

Multiple Choice

All things being equal, which of these is the most parsimonious explanation for the change in the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in the table above?

A) The occurrence of seven independent duplications of individual Hox genes.
B) The occurrence of two distinct duplications of the entire seven-gene cluster, followed by the loss of one cluster.
C) The occurrence of a single duplication of the entire seven-gene cluster.
D) Two distinct duplications of a three-gene cluster of Hox genes, followed by an independent duplication of an individual Hox gene.