What is indicated by a low number of sunspots and decreased solar activity?

The correct answer is indicative of the period known as the Maunder minimum. This term refers to a time during the 17th century when sunspot activity was significantly decreased, coinciding with what is also known as the Little Ice Age in Europe. During the Maunder minimum, observations showed very few sunspots, suggesting that the Sun's overall activity was low. This period serves as a historical reference point for understanding the relationship between solar activity and climatic conditions.

Understanding the context of solar activity is crucial, as there are different phases in the solar cycle, including solar maximum and solar minimum, which simply refer to the peak and trough of solar energy output, respectively. However, the Maunder minimum specifically delineates an extended period of exceptionally low solar activity, beyond the normal variations of the solar cycle. This is why it is the best choice for describing a situation characterized by a sustained low number of sunspots and decreased solar activity.