It may assist you to re-visit the three approaches to a maximum national limit set out before Question 3 above before considering the detail of this question.
Efallai y bydd yn eich helpu i ailedrych ar y tair ymagwedd at derfyn cenedlaethol uchaf a nodir cyn Cwestiwn 3 uchod cyn ystyried manylion y cwestiwn hwn.