Using operator delete for an abstract array that contains abstract elements - delete-operator

Question

I have the following class hierarchy and I encounter a problem when trying to use delete[] b. I get an error while compiling saying " has triggered a breakpoint!".
If I use delete b[0], delete b[1] and so on everything is ok.
Could you help me understand why delete[] is not working? Thank you.
#include <iostream>
using namespace std;
class B {
public:
B(int) { cout << "\nconstr B"; }
virtual ~B() {cout << "\ndestr B"; }
virtual char* f() const = 0;
};
class D1 : virtual public B {
public:
D1() : B(1) { cout << "\nconstr D1"; }
~D1() { cout << "\ndestr D1"; }
char* f() const { return "D1"; }
};
class D2 : virtual public B {
public:
D2() : B(2) { cout << "\nconstr D2"; }
~D2() { cout << "\ndestr D2"; }
char* f() const { return "D2"; }
};
class M : public D1 {
public:
M() : B(3) { cout << "\nconstr M"; }
~M() { cout << "\ndestr M"; }
char* f() const {return "M"; }
};
class X : public M {
public:
X() : B(4) { cout << "\nconstr X\n"; }
~X(){ cout << "\ndestr X"; }
char* f() const { return "X"; }
};
void main() {
B* b[4];
b[0] = new D1;
b[1] = new D2;
b[2] = new M;
b[3] = new X;
for (int i = 0; i < 4; i++)
cout << b[i]->f() << endl;
delete[] b;
}