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}