As is often the case in multiple-part multiple-choice questions, the answer to the first part is found in the second part. The "<em>range</em>" is the set of all possible output values.
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<h3>Part B</h3>
The range is the vertical extent of the graph. This graph goes from a minimum of 0 to a maximum of 6 and includes every value in between. The range is ...
0 ≤ f(x) ≤ 6
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<em>Additional comment</em>
You should discuss this question with your teacher. The left inequality symbol on the bottom line is pointed the wrong way.