Use the Graph to Solve the Problem $f(x)= \begin{cases}43+2.3 x & \text { for } 1970 \text { to } 1980 \\ 27+3.9 x & \text { for } 1980 \text { to } 1990\end{cases}$

Use the graph to solve the problem.
-The population (in thousands) of one city is approximated by
$f(x) = \begin{cases}43+2.3 x & \text { for } 1970 \text { to } 1980 \\ 27+3.9 x & \text { for } 1980 \text { to } 1990\end{cases}$
The graph of this function is shown below. In this graph, $x=0$ represents 1970. Use the graph to estimate the population of the city in 1979.

A) About 63,700
B) About 57,700
C) About 70,700
D) About 75,700