create a list Using combination of two types

I need to create a list in which each member is a combination of two types A and B. Is it possible? For example, assuming A and B:

class A
{
    int a1;
    string a2;
}

class B
{
    int b1;
    string b2;
}

I want to create:

List<A&B> SampleList;

in a way that A&B contains following properties:

    int a1;
    string a2;
    int b1;
    string b2;

Three options:

Create a new class or struct composing both:

public class AAndB
{
    private readonly A a;
    private readonly B b;

    public AAndB(A a, B b)
    {
        this.a = a;
        this.b = b;
    }

    // etc
}

Use Tuple<A, B> to do the same kind of thing, but without creating a new type.
If you only need this in a single method, use an anonymous type, e.g.
```
var mixed = as.Zip(bs, (a, b) => new { A = a, B = b });
```

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