Final answer:
Option C is answer. A fallacy of unwarranted assumption occurs when an argument relies on an assumption without proper justification, like claiming extraterrestrial life must exist due to lack of evidence against it.
Step-by-step explanation:
A fallacy of unwarranted assumption happens when an argument is based on a premise or belief that lacks sufficient justification. This means that the assumption is taken for granted without proper evidence. As one of the general categories of informal fallacies, it falls under the broader scope of poor reasoning in the crafting of arguments.
An example of a fallacy of unwarranted assumption is the appeal to ignorance. This occurs when one argues that a lack of evidence against a proposition proves that the proposition is true. For instance, claiming that since there is no evidence disproving the existence of extraterrestrial life, it must therefore exist, commits this fallacy. To avoid such fallacies, it's crucial to ensure that assumptions are well-supported by evidence or logical reasoning.