Answer:
The correct option is: C
Explanation:
Since we are given steps so as to prove: AB=EF
1. AD = CF----- given
2. AD = AB + BC + CD
CF = CD + DE + EF ------ segment addition
3. AB + BC + CD = CD + DE + EF ------- Transitive Property of Equality
4. AB + BC = DE + EF
5. BC = DE ------ given
6. AB = EF ------- Subtraction Property of Equality
The reason for the fourth statement in the proof is Subtraction Property of Equality.
" Since the side CD is added on both the sides of the equality; so we can subtract it from both the sides in order to obtain our statement 4 and proceed further " .
Hence option C is correct.