For the function below, find a) the critical numbers; b) the open intervals where the function is increasing, and c) the open intervals where it is decreasing. f(x) = (x + 3)4/5 a) Select the correct choice below and fill in any answer boxes in your choice. O A. The critical number(s) is/are (Type an integer or a simplified fraction. Use a comma to separate answers as needed.) O B. There is no critical number. b) Select the correct choice below and fill in any answer boxes in your choice. O A. List any interval(s) on which the function is increasing. (Type your answer in interval notation. Simplify your answer. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) O B. The function is never increasing. c) Select the correct choice below and fill in any swer boxe in your choice O A. List any interval(s) on which the function is decreasing. (Type your answer in interval notation. Simplify your answer. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) O B. The function is never decreasing.