Final answer:
Sunspots are correlated with variations in climate and weather.
Step-by-step explanation:
The relationship between sunspots and certain cyclic weather effects is that they are correlated with variations in climate and weather (option C). While the level of solar activity may not directly cause global temperature changes, it can have other effects such as affecting the chemistry and temperature structure of the upper atmosphere. This can result in changes in ozone layer, cooling of the stratosphere, and changes in wind patterns and storm tracks.