What Is the Difference Between a "Crude" and a "Specific

What is the difference between a "crude" and a "specific" rate (e.g. ,birthrate,deathrate) ?

A) Crude rates use less sophisticated statistical analyses than specific rates.
B) Crude rates are estimations based on a population sample,while specific rates are constructed from census counts.
C) Crude rates do not take account of the population distribution in any way,while specific rates do.
D) Crude rates estimate a range for a particular statistic,while specific rates give a single number.