Main trunk died

I have this maple tree whose main stem died when the tag ripped off when it went through the lawn mower. Several stems have grown underneath the damaged bit. Do I need to choose one to be the main stem or can I let them all go?

If I need to choose one, why? What will happen if I let them all grow instead?

PS it's either a silver, red, or sugar maple. I'd also like to know if knowing what kind of maple it is changes the answer.

I have zero experience and knowledge of trees, so answering like you're talking to a five year old would be greatly appreciated.