Returning const reference to local variable from a function

I have some questions on returning a reference to a local variable from a function:

class A {
public:
    A(int xx)
    : x(xx)
    {
        printf("A::A()\n");
    }
};

const A& getA1()
{
    A a(5);
    return a;
}

A& getA2()
{
    A a(5);
    return a;
}

A getA3()
{
    A a(5);
    return a;
}

int main()
{
    const A& newA1 = getA1(); //1
    A& newA2 = getA2(); //2
    A& newA3 = getA3(); //3
}

My questions are =>

1. Is the implementation of getA1() correct? I feel it is incorrect as it is returning the address of a local variable or temporary.

2. Which of the statements in main (1,2,3) will lead to undefined behavior?

3. In const A& newA1 = getA1(); does the standard guarantee that a temporary bound by a const reference will not be destroyed until the reference goes out of scope?