Assuming a \neq 3, b \neq 4, and c \neq 5, what is the value in simplest form of the following expression?

\dfrac{a-3}{5-c} \cdot \dfrac{b-4}{3-a} \cdot \dfrac{c-5}{4-b}

**Answer Choices**

A. -1

B. 1

C. \dfrac{a b c}{60}

D. \dfrac{1}{a b c}-\dfrac{1}{60}

E. \dfrac{1}{60}-\dfrac{1}{a b c}