20 PTS!!! Emma wrote the following paragraph proof showing that rectangles are parallelograms with congruent diagonals.

According to the given information, quadrilateral RECT is a rectangle. By the definition of a rectangle, all four angles measure 90°. Segment ER is parallel to segment CT and ______________ by the Converse of the Same-Side Interior Angles Theorem. Quadrilateral RECT is then a parallelogram by definition of a parallelogram. Now, construct diagonals ET and CR. Because RECT is a parallelogram, opposite sides are congruent. Therefore, one can say that segment ER is congruent to segment CT. Segment TR is congruent to itself by the Reflexive Property of Equality. The Side-Angle-Side (SAS) Theorem says triangle ERT is congruent to triangle CTR. And because corresponding parts of congruent triangles are congruent (CPCTC), diagonals ET and CR are congruent.

Which of the following completes the proof?
A. segment ET is parallel to segment RT
B. segment EC is parallel to segment RT
C. segment ER is congruent to segment CT
D. segment ET is congruent to segment CR

Emma was writing a proof to show that in rectangles diagonals are equal.For that she took the Quadrilateral RECT and used property of the Converse of the Same-Side Interior Angles Theorem .The property states :If two lines are cut by a transversal and the consecutive interior angles are supplementary, then the lines are parallel .

Emma has already taken segment ER is parallel to segment CT the other parallel segment is segment EC is parallel to segment RT .

Option B segment EC is parallel to segment RT is the right answer.