The following graphs plot the cellular response (% activation of an effector protein (y-axis)) over time (x-axis, hours) for five cell types (A to E) that have been treated with three different concentrations of a signal molecule. During the time period indicated by the horizontal gray bar underneath the X-axis, the signal molecule is present in the culture media at a concentration of 1 nM (dotted line), 5 nM (gray line), or 25 nM (black line). Note, in some graphs, the gray lines may be located close to, or the same as the black line. Analyze the graphs then answer the following question.
Which cell type shows the broadest range of response to different signal concentrations?