The function f has the property that for each real number x in its domain, 1 / x is also in its domain and
f(x)+f\left(\dfrac{1}{x}\right)=x
What is the largest set of real numbers that can be in the domain of f ?
Answer Choices
A. \{x \mid x \neq 0\}
B. \{x \mid x<0\}
C. \{x \mid x>0\}
D. \{x \mid x \neq-1 and x \neq 0 and x \neq 1\}
E. \{-1,1\}