Horizontal and parallel lines c and d are cut by transversal p. Which set of equations is enough information to prove that lines c and d are parallel lines cut by transversal p?
a) m∠1 = 81° and m∠2 = 99°
b) m∠3 = 99° and m∠4 = 99°
c) m∠2 = 99° and m∠4 = 99°
d) m∠4 = 81° and m∠1 = 81°
