Final answer:
The proposed change in company policy would require employees to recognize the income in December 2019.
Step-by-step explanation:
The effect on an employee of the proposed change in company policy for paying its salaries beginning December 2019 would be that:
a) The employee would be required to recognize the income in December 2019 because it is constructively received at the end of the month.
Under the cash method, income is recognized when it is constructively received, meaning when it is made available to the employee even if it is not physically received. Since the employee has a claim of right to the income when it is earned in December 2019, they would be required to recognize it in that year.