Consider the following parametric equations. a. Eliminate the parameter to obtain an equation in x and y. b. Describe the curve and indicate the positive orientation. x=r-4, y=r-1, -3r3 a. Eliminate the parameter to obtain an equation in x and y. y+1=(x+4)3 (Type an equation.) b. Describe the curve and indicate the positive orientation. (Type ordered pairs. Simplify your answers.) OA. A cubic curve falls to the left as r increases, starting at and ending at B. A quadratic curve falls and then rises to the left as r increases, starting at C. A quadratic curve falls and then rises to the right as r increases, starting at OD. A cubic curve rises to the right as r increases, starting at and ending at and ending at and ending at