Which one of the following is true?

A A positive statement is one which can be tested against the facts.
B A positive statement is one which never contains words such as ‘could’ or ‘should’.
C A normative statement is one which can be scientifically proven to be true or false.
D A normative statement is one which never contains words such as ‘is’ or ‘will’ or ‘always’.

The answer is A positive statement is one which can be tested against the facts.