Answer:
D.

Explanation:
Considering time as dependent variable and The rate consumption as the dependent variable. And plotting them on x and y axes respectively taking our base year as 1980(at x=0)
We are given that
In Year 1983 i.e. x= 3
Rate of consumption = 33.7
Hence our coordinates are like (3,33.7)
In year 1989 i.e. x=9
Rate of consumption = 47
Hence our coordinates are like (9,47)
Hence considering it to be an linear relation, we have two points and now we use the two point form to evaluate the relation among them
Two point form is given as
/(x_2-x_1)](https://img.qammunity.org/2020/formulas/mathematics/high-school/sgl929dccgmzmta8gih5bm0mb3pkqoxvsc.png)


Putting these values in formula






