Instructions: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Input: Which has the least initial expense, fluorescent lamps or incandescent light bulbs, or LED lamps?, Context: Objections to banning the use of incandescent light bulbs include the higher initial cost of alternatives and lower quality of light of fluorescent lamps. Some people have concerns about the health effects of fluorescent lamps. However, even though they contain mercury, the environmental performance of CFLs is much better than that of light bulbs, mostly because they consume much less energy and therefore strongly reduce the environmental impact of power production. LED lamps are even more efficient, and are free of mercury. They are regarded as the best solution in terms of cost effectiveness and robustness.
Output:
incandescent light bulbs