Which of the following functions f has a removable discontinuity at a? If the discontinuity is removable, find a function g that agrees with f for x =a and is continuous at a. (If an answer does not exist, enter DNE.) (a) f(x) = *-1, a = 1 O The discontinuity is removable. O The discontinuity is not removable. g(x) = (b) f(x) = x³ − x² - 6x, a = 3 x - 3 O The discontinuity is removable. O The discontinuity is not removable. g(x) =