Answer:
The correct option is D.
Step-by-step explanation:
It is given that
[tex]AB\cong CD[/tex]
Using definition of congruent segment.
[tex]AB=CD[/tex] .... (1)
Using segment addition.
[tex]AB=AE+EB[/tex]
[tex]CD=CF+FD[/tex]
Using segment addition in equation (1).
[tex]AE+EB=CF+FD[/tex] .... (2)
It is given that
[tex]CF\cong EB[/tex]
Using definition of congruent segment.
[tex]CF=EB[/tex] .... (3)
Using (2) and (3) we get
[tex]AE+EB=EB+FD[/tex]
Using subtraction property of equality, subtract EB from both the sides.
[tex]AE=FD[/tex]
Using definition of congruent segment.
[tex]AE\cong FD[/tex]
The missing reason is "Subtraction Property of Equality". Hence option D is correct.