Brick and carmen are in an auto accident. Brick offers carmen $2,000 if she promises not to pursue her potential legal claim against brick. Carmen agrees. Later, carmen discovers that it will cost $1,500 to repair her car and $4,000 to cover the medical expenses for a latent injury. The agreement between brick and carmen is:a. ​a release.b. ​a covenant not to sue.c. ​promissory estoppel.d. ​an illusory promise.