What Does the "90" on the Figure Indicate

Multiple Choice

What does the "90" on the figure indicate?

A) There is 90% certainty that species A₁, A₂, and A₃ are a monophyletic clade.
B) The monophyletic clade of species A₁, A₂, and A₃ appears as a monophyletic clade in 90% of all bootstrap replicates.
C) The hypothetical common ancestor for species A₁, A₂, and A₃ lived 90 generations ago.
D) The hypothetical common ancestor for species A₁, A₂, and A₃ had 90 genes in its genome.