The shipping department was asked to expedite the shipment.

The correct answer is D: Rush. The term "expedite" means to make something happen faster or to prioritize its completion. Therefore, in the context of the sentence, asking the shipping department to expedite the shipment means to speed up the process and ensure it is delivered promptly. Choice A (Cancel) contradicts the request by suggesting to terminate the shipment. Choice B (Transfer) implies moving the shipment to a different location, not necessarily speeding up its delivery. Choice C (Hold) suggests delaying the shipment, which is the opposite of expediting it. Therefore, D (Rush) is the correct choice as it aligns with the request to prioritize and accelerate the shipment process.