Given: 11. 12.request.setAttribute("vals", new String[]{"1","2","3","4"}); 13.request.setAttribute("index", "2"); 14.%> 15. 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]]}