What does a person who does not have an outhouse have?\nOptions:\n- acknowledgment\n- indoor plumbing\n- electricity\n- headache\n- feel special
Step-by-step reasoning process below:

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An outhouse is a small building containing a seat over a hole used as a toilet. People who do not have outhouses, have toilets inside the house. Indoor toilets require proper plumbing for maintenance of hygiene. The answer: indoor plumbing.
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