In terms of expectancy theory, how could Mike and Bob motivate Marco to be a great personal trainer?

One day, Marco says, $"$I$\text{'}$m working hard with my clients and I know what I$\text{'}$m doing. However, I$\text{'}$m not sure the workouts are making a difference in their lives, and that's what really makes me feel good about coming to work." In response, Mike and Bob should address

They could increase Marco's motivation by:

Giving Marco the job title "Director of Strength and Conditioning"

Reviewing fitness data on Marco's clients that show his work has been improving their health

Telling Marco he has more expertise than any other trainer at the gym

Confirming that if more clients sign up with Marco, he'll get a bonus at the end of the year