Figure 1-4 Total Revenue ($) F E Quantity Refer to Figure 1-4. Which of the following statements is true? The slope of the tangent at E and the slope of the tangent at F are negative O The slope of the tangent at E is negative and the slope of the tangent at F is positive. The slope of the tangent at E is positive and the slope of the tangent at F is negative O The slope of the tangent at E and the slope of the tangent at F are positive