The correct answer is (b), British Columbia.
British Columbia is known as the “Sea of Mountains” because it is home to the Coast Mountains, which are a mountain range that runs along the Pacific coast of North America. The Coast Mountains are the longest mountain range in British Columbia, and they are also the highest mountain range in Canada. The Coast Mountains are a popular destination for hiking, camping, and skiing.
The other options are incorrect because they are not known as the “Sea of Mountains.” Japan is a country in East Asia that is made up of four main islands. The West Coast of South America is a region of South America that is located on the Pacific Ocean. South-East Asia is a region of Asia that is located south of China and east of India.