Martha drew a pair of intersecting non-perpendicular lines, I and m. She numbered one pair of vertical angles <1 and <2, and she labeled the second pair of vertical angles <3 and <4. Martha made the conjecture that <1 =~ <2 to validate this conjecture, which of the following would be appropriate reasoning? A. M<1+ M<2 +M<3 + m<4 = 360

B. The sum of the measures of angles of a triangle is 180°

C. The measure of all right is 90°

D. Because <1 and <2 are each supplementary to <3, they are therefore congruent