Triangle PQR is transformed to similar triangle P′Q′R′ below:

A coordinate plane is shown. Triangle PQR has vertices P at negative 6 comma 6, Q at negative 6 comma 3, and R at negative 3 comma 3. Triangle P prime Q prime R prime has vertices at P prime negative 2 comma 2, Q prime at negative 2 comma 1, and R prime at negative 1 comma 1.

What is the scale factor of dilation?

1 over 2
1 over 3
1 over 4
1 over 5