Final answer:
The correct verb form to complete the sentence is 'será', which means 'will be' in English.
Step-by-step explanation:
The correct verb form to complete the sentence is será, which means 'will be' in English.
'Alejandro será médico después de dos años' translates to 'Alejandro will be a doctor after two years'.
In this context, 'será' is used because it agrees with the subject 'Alejandro' and expresses a future action.
Learn more about Verb forms in Spanish