I know that current theories in string theory state either that there are 10, 11, or 26 dimensions, but when I looked up why those numbers were chosen and not, say, 35, I could not find an answer that suited me.

As I am not an expert in string theory, can you please explain to me why (if possible in easier terms) those specific answers were chosen in regard to the number of dimensions?

I know that current string theories state that there are 10, 11, or 26 spacetime dimensions in superstring theory, M-theory, and bosonic string theory, respectively. But when I looked up why those numbers were chosen and not, say, 35, I could not find an answer that suited me.

As I am not an expert in string theory, can you please explain to me why (if possible in easier terms) those specific answers were chosen in regard to the number of dimensions?