When Modifying Data in Existing Columns,which of the Following Is

Multiple Choice

When modifying data in existing columns,which of the following is correct?​

A) ​A column must be as wide as the data it already contains.
B) ​If a NUMBER column already contains data,its precision and scale can be decreased.
C) ​Changing the default value of a column will change the values of data already in a table.
D) ​If a NUMBER column is empty,its precision and scale cannot be changed.