Need help with a b c & d. NOT E. For b, please give the answer in interval notation. Thanks

For the following function, a) give the coordinates of any critical points and classify each point as a relative maximum, a relative minimum, or neither; b) identify intervals where the function is increasing or decreasing; c) give the coordinates of any points of inflection; d) identify intervals where the function is concave up or concave down, and e) sketch the graph. k(x) =4x#+ 16x b) On what interval(s) is k increasing or decreasing? Select the correct choice below and, if necessary, fill in the answer box(es) to complete your choice. O A. The function is increasing on . The function is decreasing on (Simplify your answers. Type your answers in interval notation. Use a comma to separate answers as needed.) O B. The function is increasing on . The function is never decreasing. (Simplify your answer. Type your answer in interval notation. Use a comma to separate answers as needed.) O C. The function is decreasing on . The function is never increasing. (Simplify your answer. Type your answer in interval notation. Use a comma to separate answers as needed.) O D. The function is never increasing or decreasing