Anoche mi primo y yo la canción nueva de shakira por primera vez. a. oímos b. oyeron c. oí d. oyó

English translation:

Last night, my cousin and I Shakira's new song for the first time.

Because the subject is "my cousin and I", and because the sentence is relating to a past event, this sentence requires the first-person plural preterite conjugation.

'oyeron' is "They listened".
'oí' is "I listened".
'oyó' is "He/she/it listened".

The correct conjugation is A. oímos, or 'We listened'.