A paper triangle with sides of lengths 3,4 , and 5 inches, as shown, is folded so that point A falls on point B. What is the length in inches of the crease?

**Answer Choices**

A. 1+\dfrac{1}{2} \sqrt{2}

B. \sqrt{3}

C. \dfrac{7}{4}

D. \dfrac{15}{8}

E. 2