Which three are guaranteed to be valid for the  element of a web application deployment descriptor？（）

多项选择题Which the three EL expressions， inserted at line 15， are valid and evaluate to  3 ？ （）

A. ${vals.2 }
B. ${vals ["2"]}
C. ${vals.index }
D. ${vals[index]}
E. ${vals} [index]
F. ${vals.（vals.index）}
G. ${vals[vals[index-1]]}

单项选择题GivenaJSPerrorpage，whichimplicitobjectreferstotheuncaughtThrowablethatresultedinthepagebeinginvoked？（）

A. Error
B. Exception
C. Throwable
D. Request error
E. Request exception