The word "done" in the first paragraph can be best replaced by "______".

A．the name "A Law of Nature" is not quite adequate
B．Laws of Nature have a lot of practical and theoretical value
C．Laws of Nature do not always accurately state the nature of matters
D．"law" has two different meanings

A．custom was regarded as a part of the law
B．distinction was made between law and custom
C．changes in custom could hardly be noticed
D．a law was altered with the changes of custom