I understand how Kruskal's algorithm works. However, I am not sure how to determine the number of minimum spanning trees that a given graph has. For example say graph $G=(V,E)$ given by
When running Kruskal's you can end up with:
However, as you might note, there are several other minimum spanning trees that are still valid. An example would be getting rid of edge $BD$ and adding edge $AB$ or $CB$. So how can you determine the total number of different minimum spanning trees that exist in the graph, without having to inspect for all the different possibilities?