Final answer:
The main function of the skeletal system in relation to the muscular system is to provide attachment points for muscles, which enables movement when the muscles contract.
Step-by-step explanation:
The main function of the skeletal system in relation to the muscular system is B. to provide attachment points for muscles. Bones serve as the necessary support structure for the body and facilitate movement through their connection with muscles. When muscles contract, they pull on the bones to which they are attached, causing movement. This relationship where bones act as levers and joints serve as fulcrums is vital for all bodily movements, whether they are as simple as standing or as complex as running. Additionally, while the skeletal system does play a role in the production of blood cells and the storage of minerals, these functions are not directly related to its interaction with the muscular system.