The use of CFCs (chlorofluorocarbons) has declined since the 1987 Montreal Protocol came into force to reduce the use of substances that deplete the ozone layer. World annual CFC consumption, C = f(t), in million tons, is a function of time, t, in years since 1987. (CFCs are measured by the weight of ozone that they could destroy.)

(a) Interpret f(10) = 0.2 in terms of CFCs.

(b) Interpret the vertical intercept of the graph of this function in terms of CFCs. 

(c) Interpret the horizontal intercept of the graph of this function in terms of CFCs.