Final answer:
Katherine is likely reminding someone with the responsibility of running a union to not forget their obligations when faced with a new job opportunity, suggesting the most suitable response would be option C.
Step-by-step explanation:
The question seems to be related to a scenario where Katherine is responding to someone with a significant responsibility, such as running a union, who has been offered an exciting job opportunity. Although the exact context of Katherine's statement isn't provided, it appears she is reminding this person of their current obligations. Given the options provided, the most likely response Katherine would give is:
C. "You've got a union to run, don't forget."
This response is indicative of a reminder that current responsibilities should not be neglected for new opportunities. The other options seem to either encourage neglecting responsibilities or not considering the opportunity at all, which might not align with a responsible and supportive stance.