In the diagram, right-angled triangles AED and BFC are constructed inside rectangle ABCD so that F lies on DE. If AE=21,ED=72 and BF=45, what is the length of AB?

**Answer Choices**

A. 50

B. 48

C. 52

D. 54

E. 56

In the diagram, right-angled triangles AED and BFC are constructed inside rectangle ABCD so that F lies on DE. If AE=21,ED=72 and BF=45, what is the length of AB?

**Answer Choices**

A. 50

B. 48

C. 52

D. 54

E. 56