14.5.31In what direction is the derivative of ​f(x,y)​P(9​,2​) equal to​ zero?Select the correct choice below​ and, if​ necessary, fill in the answer box to complete your choice.A.uequalsnothing​(Simplify your answer. Use a comma to separate answers as needed. Type your answer in terms of i and​ j.)B.There is no solution.