Question

Let T: ℝ2→ℝ2 be the linear transformation that first reflects points through the y-axis and then then reflects points through the line x = y. The standard matrix of T is?
a. [0 -1]
[1 0]

b. [-1 0]
[0 -1]

c. [ 0 1]
[-1 0]

d. [1 0]
[0 1]