Gabriela is building a brick wall. Each row of bricks is 6.5cm tall except the top row which is 1cm shorter because it has no mortar. She wants the wall to be 259cm tall. Which equation can we use to determine r, the number of rows of bricks Gabriela needs in her wall?

Options:
6.5(r−1)=259
6.5r−1=259
6.5r−r=259
6.5(r− 1)+1=259