[单选题]Evaluate the following statement：   Which statemen

A  They are evaluated by all the three WHEN clauses regardless of the results of the evaluation of any other WHEN clause.

B  They are evaluated by the first WHEN clause. If the condition is true， then the row would be evaluated by the subsequent WHEN clauses.

C  They are evaluated by the first WHEN clause. If the condition is false， then the row would be evaluated by the subsequent WHEN clauses.

D  The INSERT statement would give an error because the ELSE clause is not present for support in case none of the WHEN clauses are true.