Page 709 - AP Computer Science A, 7th edition
P. 709
36. (C) In the example given, height = 3, height/2 = 1, and numCols = 3. Notice that in each pass through the loop, row has value 0, while col goes from 0 through 2. So here are the assignments:
mat[2][0] = mat[0][0] mat[2][1] = mat[0][1] mat[2][2] = mat[0][2]
From this you should see that row 2 is being replaced by row 0.