The transition from fish to tetrapods is best described as:
a) Like most of the great transitions in evolutionary history, it happened in very few big steps so that there are very few intermediates for
b) It happened gradually over millions of years with numerous intermediate forms appearing in the fossil record
c) It occurred abruptly in a single geological moment, leaving no trace of intermediate forms
d) It involved the simultaneous evolution of multiple species from a common ancestor without the need for intermediates