This code returns a reference to an object. It should compile, but something is wrong. What is wrong?

Foo& someFunction(int i)
{
Foo f;
f.doSomethingIncredible(i);
return f;
}
a. It returns a reference to a local variable that is destroyed (goes out of scope) when the function exits
b. Variable i should be passed by pointer
c. You cannot return a variable by reference

a. It returns a reference to a local variable that is destroyed (goes out of scope) when the function exits