If I were to make one invention that would change the world forever, it would be app with an alert for when your keys are either lost or stolen. An app like this would widely assist people that have had a past with their car stolen and have not had a way to track it down. Furthermore, this app would be a necessity for individuals with forgetfulness, clumsiness, and even the elderly. However, this may come with some unwanted effects thus labeling it poorly designed. For example, if the keys are said to be in an area which they are not, it may be deemed unreliable. Moreover, the key would have to have to have a tracker put on it, which may be easily removed. Nevertheless, with this idea, millions of people who spend a good chunk of their time before work will not have to stress about the difficulty of looking for their keys.
The Civil War was fought in 1861, so the answer would be D: 1800.
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