The correct answer is C. Bonus.
A bonus is a monetary reward given to an employee in addition to their regular salary. It is typically given as a reward for good performance or to recognize a special achievement.
Job security is the assurance that an employee will not be fired without good cause. It is often provided by a contract or by the terms of employment.
Effective communication is the ability to convey information clearly and effectively. It is important in all aspects of life, but it is especially important in the workplace.
Motivation is the desire to do something. It is what drives people to achieve their goals.
Of the above options, only bonus is monetary. The other options are non-monetary.