They used to be made from marble but today are made mostly from glass and plastic. Option A.
What are marbles made of?
in the past marbles were indeed made from various materials, including natural stone like marble, hence the name.
However, over time, the manufacturing process evolved, and today, marbles are predominantly produced using glass and plastic. This shift in materials has allowed for greater versatility, color options, and affordability in the production of marbles.
So the correct option is A.