Given:<br /> 11.<%<br /> 12.request.setAttribute("vals", new String[]{"1","2","3","4"});<br /> 13.request.setAttribute("index", "2");<br /> 14.%><br /> 15.<%-- insert code here --%><br /> Which 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-1]]}