Final answer:
The unethical action is 'd) Using government resources for a contractor's event', as it involves potential misuse of government resources for private benefit, contrary to ethical guidelines regarding proper use of taxpayer-funded assets.
Step-by-step explanation:
The statement that violates ethical principles in the context given is d) Using government resources for a contractor's event. This is because it may entail the misuse of government resources, such as staff time or facilities, which are meant for official public service duties rather than for the benefit of private entities. If government email accounts and staff time, which are funded by taxpayers, are being used to organize or promote an event that primarily benefits a contractor, this could be seen as an inappropriate use of public resources. Ethics in government dictate that public resources should be used for the public's benefit, and the blending of government and private resources can raise concerns about proper stewardship of taxpayer dollars. Celebrating events, sending out reminders, and holding offsite dinners are not inherently unethical, but the critical factor is ensuring that government resources are used appropriately and not for the benefit of private parties without clear justification.