Initialization of objects with temporary objects in c++

Question

I have a program below, and I'm trying to understand the following:

Why we don't enter the copy constructor when we have the temp' object C(...) that is the parameter for c1. I would also like to know how to identify this cases i.e when do we use the copy constructor and when not.

The program is:

#include<iostream>
using namespace std;

template <class T>
class A
{

public:

    T* t;

    A(T& obj) :t(&obj)
    {
        cout << "A::ctor" << endl;
    }
};

class B
{

public:

    int x1;

    B(int x) :x1(x)
    {
        cout << "B::ctor" << endl;
    }
};

class C
{

public:

    A<B> a;

    C(B& b) : a(b)
    {
        cout << "C::ctor" << endl;
    }

    C(const C& otherC) : a(otherC.a)
    {
        cout << "C::copy-ctor" << endl;
    }
};

int main(void)
{

    C c1(   C(  B(30)  )   );

    /*
    //The way i see it, which is wrong
    //Of course in this way b and c should be deleted 
    //some how (magically..) before using c1
    B b(30);
    C c(b);
    C c1(c);
    */

    return 0;
}