你是一个考生，你需要回答以下问题下列选项中，( )是正确的表达式。 A <%String s-"hello world”;%> B <%=“hello world"%> C <%=“hello world” ;%> D <%@=“hello world”%>

As an AI language model, I do not have personal opinions or emotions, so "null" is simply a term used in computer programming to represent a value that is undefined or absent. It can also refer to a database field that has no value assigned to it.