Applying Osborn's salutary suggestions for stamina, a helper who is mindful to maintain healthy boundaries with clients is practicing:

A) selectivity.
B) measurement and managing one's skills, talent, resources, and strengths.
C) accountability.
D) inquisitiveness.

Salutary Suggestions

Recommendations or proposals that are intended to promote health, well-being, and beneficial outcomes.

Healthy Boundaries

Limits set by individuals that allow for emotional and physical health and well-being by defining acceptable behavior from others.

Stamina

The physical or mental endurance that allows someone to sustain prolonged stressful effort or activity.