According to the passage, which of the following statements about the cell phone service a

According to the passage, which of the following statements about the cell phone service at Yellowstone is TRUE？

A．It is limited certain areas in the park.

B．It is available everywhere in the park.

C．It is not available in the park.

D．It is available to visitors at a fee.

请帮忙给出正确答案和分析，谢谢！