Select the correct answer. Given: ∆ABC Prove: A midsegment of ∆ABC is parallel to a side of ∆ABC. Statement Reason 1. Define the vertices of ∆ABC to have unique points A(x1, y1), B(x2, y2), and C(x3, y3). given 2. Let D be the midpoint of and E be the midpoint of . defining midpoints 3. definition of midpoints 4. slope of slope of definition of slope 5. slope of = slope of Transitive Property of Equality 6. definition of parallel lines 7. Let F be the midpoint of . defining a midpoint 8. definition of midpoint 9. slope of slope of definition of slope 10. 11. definition of parallel lines 12. Similarly, is parallel to . steps similar to steps 1−11 What is the missing step in this proof? A. Statement: slope of = slope of Reason: definition of slope B. Statement: slope of = slope of Reason: Transitive Property of Equality C. Statement: DF = BC Reason: Corresponding sides of congruent triangles are congruent. D. Statement: ∆ADF ≅ ∆ABC Reason: ASA