The underlined word "event" ( Paragraph 1 ) refers to______.

A．Telling people how serious the damage caused by landslides is.
B．Telling people that sending workers to stabilize mountainsides is a risky job.
C．Introducing a product that can be used to stabilize mountainsides.
D．Showing people how to use a new product.

A．it will be faster and cheaper than manual labor
B．it can climb mountainsides, drill holes, insert bars and cement
C．it can collect data on the slope' s stability
D．it can drill without a human being on board