Which element， defined as a child of a  element in the web application deployment descriptor， guarantees a servlet will be initialized at the time the application is deployed？（） 

• A、 <load-on-startup/> 
• B、 <load-on-startup>1</load-on-startup> 
• C、 <load-on-startup>-1</load-on-startup> 
• D、 <load-on-startup>true</load-on-startup>