Answer:
B.the Cambrian period
Step-by-step explanation:
The most recent types of body plans appeared during the Cambrian period. The Cambrian period is known as the "Cambrian explosion" because it was a time when there was a rapid diversification of life on Earth, and many new body plans appeared. During this time, there was an explosion of biodiversity, and many of the major animal phyla that exist today first appeared, such as arthropods, chordates, and echinoderms. The Cambrian period is therefore an important time in the history of life on Earth, as it marked the beginning of the development of many of the complex body plans that exist today.