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[ Option B ]

In C++, when working with files, the open() method of file streams allows you to specify the mode in which the file should be opened.

• It is possible to combine two or more file opening modes using the bitwise OR operator (|). For example, fstream file("myfile.txt", ios::in | ios::out); opens a file for both reading and writing. Therefore, statement 1 is incorrect, and statement 2 is correct.
• The ios::in is used to open a file in input (reading) mode and ios::out is used to open a file in output (writing) mode. So, statement 3 is correct.

[ Option C ]

In C++, file streams use modes to control how files are opened and accessed. The ios::trunc is a file mode used with output streams. Its purpose is to truncate an existing file, which means it deletes all the current content of the file and makes its size zero before writing new data.

• If the file does not exist, it will be created.
• Usually, ios::trunc is used with ios::out mode while opening a file for writing.

#include <fstream>
using namespace std;
int main() {
    ofstream file("myfile.txt", ios::out | ios::trunc);
    file<<"New Content Added.";
    file.close();
    return 0;
}