Audrina constructed a proof that quadrilateral PQRS is a rectangle.
In the proof below, she started with a pair of observations about the plot of quadrilateral PQRS on the coordinate plane.
With which pair of observations did Audrina start her proof?
A) Slope of PQ = Slope of RS = 3 ; Slope of PS = Slope of QR = 1/3
B) Slope of PQ = Slope of RS = 3: Slope of PS = Slope of QR = − 1/3
C) PQ = RS = 2√10 ;PS = QR = √17
D) PQ = RS = 6; PS = QR = 4