Final answer:
The correct verb form to complete the sentence is 'decida'.
Step-by-step explanation:
The correct verb form to complete the sentence is decida. The verb form must agree with the subject 'yo' which is first-person singular. In this case, 'decida' is the correct conjugation of the verb 'decir' (to say) in the present subjunctive form.
Learn more about Spanish verb conjugation