What will be the output of the following C# code snippet?

unsafe static void Main()
{
    int a = 5;
    int b = 5;
    int c = 5;
    int*[] ptr = new int* [3];
    ptr[0] = &a;
    ptr[1] = &b;
    ptr[2] = &c;
    for (a = 0; a < 3; a++)
    {
        c += *ptr[a];
        Console.WriteLine(c);
    }
    Console.ReadLine();
}

What is the purpose of the "using" keyword in C#?

A. To define namespaces

B. To declare variables

C. To import external libraries

D. To create instances of classes

What does the "break" keyword do in a switch statement?

A. Exits the switch statement

B. Skips the current iteration

C. Continues to the next iteration

D. Throws an exception

Which of the following is NOT a valid C# access modifier?

A. public

B. internal

C. protected

D. private

What is the purpose of the "readonly" keyword in C#?

A. To declare a constant

B. To prevent a variable from changing

C. To allow a variable to be changed

D. To declare a static variable