1. Member States shall ensure that each of the tasks laid down in this Directive is undertaken by a competent authority. Within the scope of this Directive, the national regulatory authorities shall be responsible at least for the following tasks:

(a) implementing ex ante market regulation, including the imposition of access and interconnection obligations;

(b) ensuring the resolution of disputes between undertakings;

(c) carrying out radio spectrum management and decisions or, where those tasks are assigned to other competent authorities, providing advice regarding the market-shaping and competition elements of national processes related to the rights of use for radio spectrum for electronic communications networks and services;

(d) contributing to the protection of end-user rights in the electronic communications sector, in coordination, where relevant, with other competent authorities;

(e) assessing and monitoring closely market-shaping and competition issues regarding open internet access;

(f) assessing the unfair burden and calculating the net cost of the provision of universal service;

(g) ensuring number portability between providers;