Answer: the highest of the minimum wages.
Step-by-step explanation:
The company will have the pay the minimum wage that is the highest because they are under the authority of all three governments and paying the highest minimum wage would ensure that they automatically follow the minimum wages set by the other two authorities.
For instance; the federal minimum wage is $7.25 per hour, the state minimum wage is $10 per hour and the city minimum is $12 per hour. When the company pays $12 an hour, they would be adhering to the city minimum and automatically adhering to the Federal and State minimums as well.