System.out.println(Math.sqrt(-4D));  What is the result?()  
A、A. –2
B、B. NaN
C、C. Infinity
D、D. Compilation fails.
E、E. An exception is thrown at runtime.
A、A. –2
B、B. NaN
C、C. Infinity
D、D. Compilation fails.
E、E. An exception is thrown at runtime.
A、foreach(x)
A、