Which of the following constitutes termination of employment by operation of law?

A. Death of employer, in case of personal service
B. Breach by either of the parties
C. Compulsory winding-up of employer’s company
D. Illness of the employee
E. Agreement by both parties

A. Death of employer, in case of personal service

Explanation:
In cases of personal service (such as employment contracts where the employer’s personal involvement is essential), the death of the employer automatically leads to the termination of the employment relationship by operation of law, as the employee cannot continue to work under the contract.