What is the missing reason in the proof?
A 2-column table has 5 rows. Column 1 is labeled Statement with entries line segment N G is-congruent-to line segment J G, angle N and angle J are right angles, angle M G N is-congruent-to angle K G J, angle N is-congruent-to angle J, triangle M N G is-congruent-to triangle K J G. Column 2 is labeled reason with entries given, given, vertical angles are congruent, right angles are congruent, and question mark.