Answer:
It stores memories of previously learned movement patterns.
It regulates activity along the voluntary and involuntary motor pathways.
It subconsciously coordinates minute muscle movements. (if it is one of your options)
Explanation:
Cerebellum is responsible for regulating fine tune muscle movements as the question specifies. It does by receiving input from motor cortex, sensory receptors and stem nuclei and act as regulator in between voluntary and involuntary movements. It also stores memories which are called "muscle memories" like cycling or driving a car. While cycling you don't actually "think" all of your movements so it acts subconsciously.