A foreign student from Minamata, Japan was narrating to her peers about a disease that occured back in her home area some 50 years ago. She said the local fishermen regarded it as "the disease of the dancing cats". The symptoms included blurred vision, fatigue, irritability, headaches, and numbness in arms and legs. Scientists conducted an investigation and found out that the culprit was a heavy metal. Which of the following metals was the cause of the disease?
a. chromium
b. cadmium
c. mercury
d. arsenic