Final answer:
The domain for the function describing the number of lightbulbs packaged in terms of defective bulbs is best represented by non-negative integers since packaging cannot be negative or fractional.
Step-by-step explanation:
The option that best describes the domain of the function that takes the number of lightbulbs packaged in a day and produces an output of the approximate number of defective bulbs is A) Non-negative integers. This is because you can't package a negative number of lightbulbs, and typically, packaging is done in whole units rather than fractions; hence, real numbers, negative numbers, or fractions don't make sense in this context. Therefore, the domain consists of all whole numbers starting from zero (which includes zero), reflecting the possible numbers of bulbs a factory could package in a day.