A 2-column table has 8 rows. The first column is labeled Statements with entries angle A B C is right angle, Line segment D B bisects angle A B C, B, m angle A B D = m angle C B D, m angle A B D + m angle C B D = 90 degrees, m angle C B D + m angle C B D = 90 degrees, D, m angle C B D = 45 degrees. The second column is labeled Reasons with entries A, given, definition of right triangle, definition of bisection, C, substitution property, addition, and division property. Identify the missing parts in the proof.
Given: ∠ABC is a right angle.
DB bisects ∠ABC.
Prove: m∠CBD = 45°
A:
B:
C: