The discontinuities in graphs $(a)$ and (b) are removable discontinuities because they disappear if we define or redefine $f$ at a so that $f(a)=\lim _{x \rightarrow a} f(x) .$ The function in graph (c) has a jump discontinuity because left and right limits exist at a but are unequal. The discontinuity in graph $(d)$ is an infinite discontinuity because the function has a vertical asymptote at a.
Is the discontinuity at $a$ in graph (c) removable? Explain.