Check the statements below that are true.

a. a single vector by itself is linearly dependent.
b. a basis is a spanning set that is as large as possible.
c. the columns of an invertible n×n matrix form a basis for rn.
d. if v=span{v1,}, then {v1,} is a basis for v.
e. in some cases, the linear dependence relations among the columns of a matrix can be affected by certain elementary row operations on the matrix.