Answer:
C. Subtraction property of equality.
Explanation:
Given AD= CF
And BC=DE
To prove that AB=EF
Proof:
1.Statement: AD=CF
Reason: Given in question.
2. Statement: AD= AB+BC+ CD, CF= CD+DE+EF
Reason: Segment addition property because AB,BC,and CD are the segments of AB and CD,DE and DE are segments of CF.
3. Statement: AB+BC+CD=CD+DE+EF
Reason: Transitive property of equality
Transitive property: If ab=bc and bc=ca
Then , ab=ca
4.Statement: AB+BC= DE+EF
Reason: By using subtraction property of equality.
5. Statement:BC=DE
Reason: Given in question.
6. Statement: AB=EF
Reason: when we put BC=DE . Then we get AB+DE=DE+EF. By using subtraction property of equality .
Hence proved .