Any vector in the direction of the gradient will be an answer to the second question, since they just ask which is in the right direction; the gradient divided by its length is specifically the unit vector in that direction. It happens that all the options shown are unit vectors; so that formula gives the answer. If that were not true, you could just check the ratio of components of each vector.
I presume you found that the gradient is <1, 0>, which happens to be a unit vector, so that is the answer.