To show a translation of a hexagon 7 units to the left on the coordinate grid, you need to adjust the x-coordinates of the hexagon's vertices.
When you shift a point (x, y) to the left by 7 units, the new x-coordinate becomes \( x - 7 \). The y-coordinate remains unchanged.
So, the function that represents this translation would be:
\[ f(x) = x - 7 \]
Thus, the correct answer is:
C. f (x) = x - 7