The organism at point W is a bony fish. The organism at point X is a dinosaur. The organism at point Y is a trilobite. The organism at point Z is an amphibian. This diagram suggests that
A.
dinosaurs became extinct before the evolution of bony fishes.
B.
trilobites are the oldest living creatures on the planet.
C.
amphibians are common ancestors of dinosaurs and trilobites.
D.
different species were abundant at different times in Earth's history.