Brady runs for his high school cross country team. His strategy for each 5-kilometer race is always the same. He begins by increasing his speed so that by the time he reaches the first kilometer, he is running at a speed of 0.3 km/min. He then maintains that speed for the next 2 kilometers. He then gradually speeds up for the remaining 2 kilometers so that when he crosses the finish line he is running at a speed of 0.5 km/min.

What is the next step in the given proof? choose the most logical approach. a. statement: m 1 + m 2 + 2(m 3) = 180° reason: angle addition b. statement: m 1 + m 3 = m 2 + m 3 reason: transitive property of equality c. statement: m 1 = m 2 reason: subtraction property of equality d. statement: m 1 + m 2 = m 2 + m 3 reason: substitution property of equality e. statement: 2(m 1) = m 2 + m 3 reason: substitution property of equality