In triangle xyz, m∠z > m∠x + m∠y. which must be true about △xyz?

m∠x + m∠z < 90°
m∠y > 90°
∠x and∠y are complementary
m∠x + m∠y < 90°

What would be the reasons for lines 3 and 4? a. addition property; subtraction property b. addition property; solve c. substitution property; subtraction property d. substitution property; prove