Which is not one of the leadership practices that Kouzes and Posner identify for effective leadership?

Enable Others to Act is the fourth of the five official practices in the Kouzes and Posner leadership model.

Persuade is not included in any of the Five Practices of Exemplary Leadership identified by Kouzes and Posner; the five practices are Model the Way, Inspire a Shared Vision, Challenge the Process, Enable Others to Act, and Encourage the Heart - none of which involve a persuasion-based practice.

Note - including C (Model) as a correct answer appears to be an error in the question; Model the Way is in fact the first of Kouzes and Posner's five practices and is a core element of their Leadership Challenge framework.

Encourage the Heart is the fifth of the five official practices in the Kouzes and Posner leadership model.