Final answer:
The correct option is a - Employer may implead Driver under Rule 14. The employer can bring the driver into the lawsuit to seek indemnification.
Step-by-step explanation:
The correct option in this scenario is a - Employer may implead Driver under Rule 14.
When the plaintiff sues both the driver and the employer, the employer can implead the driver by bringing him into the lawsuit as a third-party defendant. This is allowed under Rule 14 of the Federal Rules of Civil Procedure. By doing this, the employer is seeking to have the driver indemnify or reimburse them for any damages they may be liable for.
Option b is incorrect because a crossclaim is typically filed by one co-defendant against another co-defendant in the same lawsuit. Option c is also incorrect because there is no requirement for the employer to file a crossclaim against the driver for contribution. Lastly, option d is incorrect because the joinder of both the driver and employer in the lawsuit is appropriate given the circumstances of the case.