A function g is differentiable on (−∞,2)∪(2,∞) but not at x=2. Suppose g′(x)<0 for every x<2 and g′(x)>0 for every x>2. Which of the following must be true?
a) g increases on (−∞,2) and decreases on (2,∞).
b) g decreases on the entire real line.
c) g decreases on (−∞,2) and increases on (2,∞).
d) g increases on (−∞,2) and also increases on (2,∞).