Which of the following nerve involved in-opening inlet of larynx?

All intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve except for the cricothyroid which is supplied by the external laryngeal nerve. The cavity of larynx extends from the inlet of the larynx to the lower border of the cricoid cailage.the inlet of the larynx is placed obliquely.it looks backwards and upwards and opens into the laryngopharynx. Ref BDC volume 3;Sixth edition pg 257