a) Which of the following represents the set of all linear combinations of the columns of matrix A?

A) 2 4 2 0 6 1 8 5 1 2 1 3 5
B) 2 4 10 3 3 3 5
C) Let W be the set of all linear combinations of the columns of A.

b) To demonstrate that the third column of matrix A is in the set of all linear combinations of its columns, we would:

A) Compare the third column of A to the first column of B.
B) Show that the third column of A can be expressed as a combination of the columns of B.
C) Multiply the third column of A by a scalar.