Lane Applies for a Firefighter's Job with Metro City, Which

Lane applies for a firefighter's job with Metro City, which responds with a letter setting an appointment for a medical exam. The letter also states that it is "an employment offer conditioned on the applicant passing the exam." This is

A) ​a bilateral contract that Lane accepted by applying for the job.
B) ​a quasi contract on which Lane can rely for employment.
C) ​a unilateral contract that Lane can accept by passing the exam.
D) ​no contract.