Answer:
b. discharges the employer from the contract.
Explanation:
When an employee enters a contract with the employer there is an agreement that the employee will perform their duties effectively (in this case Emma as a billing manager) and the employer is obligated to pay her for services provided.
If Emma is failing to meet his obligations by being absent from work and even when present fails to adequately do her job, the employer is also discharged from his agreed duty on the contract.
Emma's actions discharges the employer from the contract.