Transversal t cuts parallel lines a and b as shown in the diagram. Which equation is necessarily true?
A. m∠1 = m∠2
B. m∠4 = m∠6
C. m∠1 + m∠5 = 90°
D. m∠3 + m∠5 = 180°
E. m∠7 = m∠8
