You Eat M&Ms Every Day

You eat M&Ms every day. When you go to the store to buy some, you find that M&Ms are more expensive than they were last month. Which of the following could explain why M&Ms are more expensive?

A) Consumers are now purchasing fewer M&Ms compared to other types of chocolates.
B) A new robot has been installed at the Mars chocolate company that reduces the time needed to produce M&Ms by half.
C) A new study finds that the benefits of eating chocolate are not as great as previously thought.
D) The supply of cacao beans, used to produce chocolate, has fallen around the world.