I would add, you probably don't want the first one. Even if you want something like a two-dimensional array, it's a bad idea to mix lists with arrays - you will tend to get confusing error messages in the future. If you want something like this, you are probably better off with either a List of Lists, or an array of arrays. But not an array of lists, or a list of arrays.
More likely, you just wanted a single list in the first place. Which is what you get with line #2 above. Just use that.