Answer:
The answer is B
Statement: slope of DF = slope of BC
Reason: Transitive Property of Equality
Explanation:
∵ He find the slope of BC from point B and point C
∵ He find the slope of DF from the mid-point of AB ad the mid-point of
AC
∵ The two answers are equal
∴ The two slopes are equal
∴ Statement is slope of DF = slope of BC
∴ Reason is transitive property of equality