Hi!

I'm spanish so I hope that span means... ehm "make" . If you have a vector space for example , then the dimension is n. The dimension of a vector, as far as I know, it's a maximal set of linear independent vectors or a minimal set of "generator" vectors. In practise it's the number of vector that every base should have. In our case as then the dimension is .

With this in mind, option 1) doesn't have 3 vectors so it can't span . 2) Four vectors, it can be a good candidate. If there are 3 or more linearly independent then it's ok. This is the math around this.

To proof if they are or not linearly independent, just look if there is a determinant of a matrix that have as rows or columns your vectors, different of zero.

Hope it helps