A. After conclusion of a hearing on an application for a certificate of convenience and necessity the commission shall make and file an order containing its findings of fact and decision. The order shall become operative twenty days after issuance, except as the commission may otherwise provide.

B. The commission shall grant all certificates as required by Section 4 [63-9-4 N.M. Stat. Ann.] of this act.

C. As to all applications other than those based upon Section 4 of this act, the commission has the power, after having determined public convenience and necessity, to grant a certificate as applied for, or to refuse to grant it, or to grant it for the construction or operation of only a portion of the contemplated plant or system or extension thereof, or for the partial exercise only of the rights and privilege sought, and may attach to the exercise of the rights and privilege granted by a certificate such terms and conditions as in its judgment the public convenience and necessity may require.

D. The geographical field or area that a telephone company is authorized and required to serve by a certificate shall be defined on a map which will be part of the certificate. The commission shall prescribe the form of the map to be used.