4. A shopping mall has a triangular parking lot, as shown in the diagram. Q(-2,3) R(6-1) P(-5-3) Jason wants to prove that POR is a right angle.
He set up the following correct calculations.
1. PQ= sqrt ( - 5 - (- 2) ^ 3 + (- 3 - 3) ^ 2

2. PR = sqrt(- 5 - 6) ^ 2 + (- 3 - (- 1) ^ 2)

3. QR = sqrt(- 2 - 6) ^ 2 + (3 - (- 1) ^ 2)

4. Slope( overline PQ )= (- 3 - 3)/(- 5 - (- 2))

5. Slope( overline PR )= (- 3 - (- 1))/(- 5 - 4)

6. slope (QR) = (3 - (- 1))/(- 2 - 4)
Which combinations of these calculations are enough to prove that angle PQR is a right angle?

A 1 and 2

B. 4 and 6

C. 1, 4, and 5

D 4 and 5

E. 1 and 3

F. 1, 2, and 3​