Questions 14-16 are based on the following passage. You now have 15 seconds to read questions 14-16.

Which of the following is not mentioned in the talk

A．The early Indians cooked their food by burying it under the hot sand.
B．Raw food has been eaten for thousands of years.
C．The earlier kitchen utensil was very simple.
D．Boiling food became possible after fire-proof containers appeared.