A conjecture and a portion of the flowchart proof used to prove the conjecture are shown. Which equation best represents the information that should be in the box labeled 1? O 2a + 4 = 20 O 4a + 4 = 20 O 4a = 10 O 2a = 20 Given: XYYZ XY = 4a + 4 YZ = 20 Prove: a = 4 XY = 4a + 4 Given XY YZ Given 1 N 20 4a + 4 XY = YZ Segment Congruence Postulate Substitution Property of Equality 4a = 16 Subtraction Property of Equality a = 4 Division Property of Equality X YZ = 20 Given​