employer on the grounds

Grace was fired by her employer on the grounds that she always showed up late to her work shifts. Assuming that the law of employment-at-will holds in the given scenario, which of the following statements is most likely true?
A.
Grace can get her job back using the A????1implied contractA????1 exception to employment-at-will.
B.
Grace should accept the decision, because the company did nothing illegal.
C.
Grace can get her job back using the A????1public policyA????1 exception to employment-at-will.
D.
GraceA????1s employer is committing the most commonly seen federal crime.