Which word would best describe a factor that serves as a solution to a pressing issue?

The word that best describes a factor that serves as a solution to a pressing issue is "provisional." This term typically refers to something temporary or conditional that is put in place to address an immediate need or situation. In the context of a pressing issue, a provisional factor can be seen as a stopgap measure or a temporary solution designed to alleviate the problem until a more permanent resolution can be found. This makes it particularly relevant in urgent scenarios where immediate action is necessary.

The other options do not convey the same sense of providing a solution to an issue. A pseudonym refers to a fictitious name, often used by authors, which doesn’t relate to solving problems. Prudent implies being cautious and wise, but does not specifically indicate an immediate solution. Quack typically refers to someone pretending to be a professional or expert, especially in medicine, and implies deceit rather than addressing an issue effectively.