Final answer:
Values between 4.5 and 5.5 would be measured as 5 when rounded to the nearest whole number with an instrument that measures in units of 1.
Step-by-step explanation:
When an instrument measures in units of 1, it typically rounds to the nearest whole number. In the context of this question, a value would be measured as 5 if it falls in the range where it is closer to 5 than to any other whole number. This range would be from the midpoint between 4 and 5 to the midpoint between 5 and 6. Therefore, any value greater than or equal to 4.5 and less than 5.5 would be rounded to 5. Hence, the correct answer is (c) 4.5 and 5.5. This is because if the value is, for example, 4.49, the instrument would round it down to 4, and if the value is 5.51, the instrument would round it up to 6.