After the declaration of the outf as output file stream, what happens when you execute the following C++ statement outf.open ("ABC.txt", ios append); Select one: O a. The new output will be written at the end of the file O b. The output file will be encrypted O c. The output file will be used for input instead O d. The existing content of the file ABC.txt will be overwritten O e. The file ABC.txt will be displayed on the screen