The line y=x is transformed to create the line y=- 1/2 x-1. Which of the following may be used to describe the transformation?

a. All x -values are opposites of half the original x -values.
b. The graph is reflected across the y-axis, moved 1 unit down, and the rate of change is halved.
c. All x -values are half the original x -values.
d. The graph is reflected across the y-axis, moved 1 unit down, and the rate of change is doubled.