According to evolutionary theory, species that exist today are the result of a slow, continuous change of living things over time. Why is this considered to be a theory and not a law?

A. Evolutionary theory is a description based on observations. A law is based on mathematical calculations.
B. Evolutionary theory is an educated guess. A law is supported by extensive research.
C. Evolutionary theory may change when new evidence is found that does not support the theory. A law has been proved with scientific evidence.
D. Evolutionary theory is an explanation of how living things have changed over time. A law describes natural events but does not attempt to explain them.