Final answer:
Miso is a fermented Japanese bean paste that can be aged for up to 3 years before being used to make soup.
Step-by-step explanation:
The correct answer is a) Miso. Miso is a traditional Japanese fermented bean paste that is commonly used to make soup. It is made by fermenting soybeans with salt and a koji starter culture. The fermentation process can take anywhere from a few weeks to several years, with some miso being aged for as long as three years before it is used.