Which statement correctly describes the relationship between the graph of f(x)=8xf(x)=8x and the graph of g(x)=4f(x)g(x)=4f(x) ?
a. the graph of g(x)g(x) is translated 4 units left from the graph of f(x)f(x) .
b. the graph of g(x)g(x) is translated 4 units right from the graph of f(x)f(x) .
c. the graph of g(x)g(x) is a horizontal stretch of the graph of f(x)f(x) by a factor of 4.
d. the graph of g(x)g(x) is a vertical stretch of the graph of f(x)f(x) by a factor of 4.?