The average cost a to manufacture x items is modeled as a = 5+x/x, where a is expressed in dollars. which statement about function a is true?

a) the vertical asymptote lies at x = -5
b) the horizontal asymptote lies at a = 1
c) the vertical asymptote lies at x = -5
d) the horizontal asymptote lies at a = 2
e) the average cost of manufacturing very large items is almost $5