What Is True About the Following Statement? Out

Multiple Choice

What is true about the following statement? out.open("values.dat", ios::app) ;

A) If the file already exists, its contents are preserved and all output is written to the end of the file.
B) If the file exists, it should be replaced with a new copy of values.dat
C) If the file exists, it can be opened but not modified
D) None of these