Let t be an linear transformation from rr to rs. let a be the matrix associated to t fill in the correct answer for each of the following situations 1. two columns in the row-echelon form of a are not pivot columns. 2. the row-echelon form of a has no column corresponding to a free variable. 3. every column in the row-echelon form of a is a pivot column. 4. the row-echelon form of a has a column corresponding to a free variable. a. t is not one-to-one b. t is one-to-one c. there is not enough information to tell