Which of the following best describes the purpose of the writer’s use of source material in the essay?
(A) The writer moves beyond her personal experiences to show the
negative effects of lying on a wide range of people and events.

(B) The writer refers to outside sources to justify her belief that lying
is part of our culture.

(C) The writer describes a series of hypothetical cause-and-effect
sequences to show the dangers of lying.

(D) The writer exploits real and hypothetical situations where lying
had adverse effects to warn parents about the dangers of lying.

(E) The writer integrates excerpts from others’ personal experiences
to underscore the ubiquity of lying in our culture.

You need to figure out at which x-value does the graph has a tangent line slope of -1.remember, the derivative is the slope of the tangent line. so find the derivative function and set it to equal -1 to find the x-value that will have a tangent line slope of 0.differentiate with the chain rule.    set the derivative to equal -1 and solve for x.      take log base 10 of both sides. also recall that  .    so the x-coord of the point of tangency is .the y-coordinate of this point of tangency can be calculated using the original function:     using point-slope form, the equation of the tangent line is      the x-intercept of this tangent line is when the graph is at y=0.    this rounds off to  .choice c.