Step 6 wants us to show two angles which are also two interior angles that are located on the same side.
Interior angles are angles that are INSIDE the parallel lines.
On the diagram given, there are two pairs of interior angles that are on the same side:
Angle VQT and angle ZRS
Angle UQT and angle WRS
Two interior angles on the same sides add up to 180°
The missing statement that would fit statement in Step 6 is:
m∠VQT + m∠ZRS = 180°
Answer: Second option