Only two points are necessary to determine the equation for a straight line. When using the scatter-graph method to estimate the flexible budget cost function, the two points used are:

		a. the Y-intercept and the midpoint of the observed data points.
		b. the Y-intercept and the data point at the highest observed level of activity.
		c. the data point at the highest observed level of activity and the data point at the lowest observed level of activity.
		d. the Y-intercept and the data point at the lowest observed level of activity.