Ratio of max (x+y) to min (x-y)

To maximize (x+y), we take the maximum possible values for both variables: \max(x) + \max(y) = 8 + 7 = 15. To minimize (x-y), we must start with the smallest possible value for x and subtract the largest possible value for y: \min(x) - \max(y) = 4 - 7 = -3. The required ratio is the maximum value divided by the minimum value. Ratio = 15 / -3 = -5. Since -5 is not among the given numerical choices, the correct option is "None of the above".

Answer: (d).