Letters a, b, c, and d are angles measures. Lines m and n are cut by transversal p. At the intersection of lines p and m, labeled clockwise, from uppercase left, the angles are: a, b, c, blank. At the intersection of lines p and n, labeled clockwise, from uppercase left, the angles are: blank, blank, d, blank.

Which equation is enough information to prove that lines m and n are parallel lines cut by transversal p? Select three options.

a = c
a = d
c = d
b + c = 180°
b + d = 180°