Answer: Choice B
The function f is continuous on

There is a removable discontinuity at x = 0.
====================================================
Step-by-step explanation:
Let

The f(x) function changes its identity based on what the input x would be.
If x < 0, then f(x) = g(x)
If x > 0, then f(x) = h(x)
Plug x = 0 into g(x)

Do the same for h(x)

Both functions produce the same output (2) when x = 0. Therefore, the two pieces are connected. Both pieces approach y = 2 when x gets closer and closer to zero. But we'll have an open hole at x = 0 since neither piece is defined when x = 0. This makes f(0) undefined. We have a removable discontinuity at x = 0. This is in contrast to a jump discontinuity where the two pieces do not approach the same y value.
To express this in interval notation, start with the set of real numbers
and poke a hole at x = 0 to remove it.
We'll end up with
as the domain and where f(x) is continuous.
Refer to the graph below.