Final answer:
The correct infinitive reflexive verb is 'tener'.
Step-by-step explanation:
The infinitive form of the reflexive verb that correctly completes the sentence is '6 - tener'.
In the given sentence, 'Para no hay que comer muchas frutas y verduras, hacer ejercicio, dormir bien y tener una rutina saludable', the reflexive verb is used with the pronoun 'se'. Therefore, the correct form is 'tenerse' which translates to 'to take care of oneself' in English.
For example, 'Tenerse en cuenta' means 'to take oneself into account' or 'to take care of oneself'.
Learn more about Infinitive reflexive verbs in Spanish