which statement completes step 6 of the proof?

coordinate plane with line f at y equals 3 times x plus 1 and line g at y equals negative one third times x plus 1. triangle jkl is at j negative 1 comma negative 2, k 0 comma 1, and l 0 comma negative 2. triangle j prime k l prime is at j prime negative 3 comma 2, k 0 comma 1, and l prime negative 3 comma 1.

step 1 segment kl is parallel to the y-axis, and segment jl is parallel to the x-axis.
step 2 δjkl was rotated 90° clockwise to create δj'kl'. point k did not change position, so it remains point k. therefore, δjkl ≅ δj'kl'.
step 3 segment k l prime is perpendicular to the y-axis, and segment j prime l prime is perpendicular to the x-axis.
step 4 segment jk lies on line f and has a slope of 3.
step 5 segment j prime k lies on line g and has a slope of negative one third.
step 6 ?
the product of the slopes of segment jk and segment j prime k is −1; therefore, lines f and g are perpendicular.
the slopes of segment jk and segment j prime k are congruent; therefore, lines f and g are parallel.
the product of the slopes of segment kl and segment k l prime is −1; therefore, lines f and g are perpendicular.
the slopes of segment kl and segment k l prime are congruent; therefore, lines f and g are parallel.