Answer: Option (D) is correct.
Explanation:
Correct option: Better employment opportunities in a closely-related job.
There is a shift in the market supply curve if there is any changes in the employment opportunities in a closely related to the job. Suppose there are more employment opportunities in a closely related field in the economy as a result market labor supply curve shifts leftward.
Alternatively, if there is a contraction of employment opportunities then this will results in a rightward shift of the market labor supply curve.