Which of the following would be a valid tensor equation you

Question

Problem:

Which of the following would be a valid tensor equation? You should indicate if the equation is valid; and if it is not valid, you should state why.

a_ij = u_iv_j ∂w_j/∂x_i

Additional Information:

This problem is from Mathematics as well as it is about valid tensor equation and find the validity of the equation.