Answer the following question given this paragraph: Coal has different grades. Bituminous coal forms at lower temperatures. It contains a lot of sulfur. When it is burned, it causes a lot of pollution. Anthracite coal forms under higher temperatures. This drives off the sulfur, and the coal burns more cleanly. Q: What type of coal is formed at lower temperatures? Choices: - clean - calcareous - limestones - bituminous A:
Answer:
bituminous