thankyou!:)

Which of the following options can be used to replace: [?] A. vec[i][i] += num B. vec[i] = num + vec[i] C. vec[i][i] = num The following method attempts to add the value num from each element on the diagonal of the 2D array vec. You may assume that vec is a square matrix, that is, you may assume vec. length == vec[0].length