What is the domain and range of the step function below?
a. domain = {all real numbers}, range = {all real numbers}
b. domain = {all real numbers}, range = {–4, –1, 2, 5, }
c. domain = {–5, –2, 1, 2, }, range = {–4, –1, 2, 5, }
d. domain = {all integers}, range = {all real numbers}

Option: B

As the x-xis is defined by a arrow sign on both sides it means that the x-axis is extending infinitely in both the directions.

The domain of a function is the set of values where a function is defined.

Hence from the graph we could see that the function is defined all over the real numbers as the function takes some integer values for all of the real numbers.

Domain={all real numbers}

Also Range of a function is the value that is attained by the function in the domain.

Hence, from the graph we could observe that the range of the function is:

Range={-4,-1,2,5,}

the graph on the bottom right