Which medication is contraindicated in patients with milk and soy allergies?

The correct choice, Relenza Diskhaler, is contraindicated in patients with milk and soy allergies due to its formulation. This medication contains lactose, a sugar derived from milk, which can trigger allergic reactions in individuals who are sensitive to milk proteins.

In contrast, the other options—Sovaldi, Harvoni, and Vosevi—do not contain milk or soy products in their formulations. These medications are antiviral agents used for treating hepatitis C, and their ingredient lists do not include components that would pose a risk to patients with allergies to milk or soy. Thus, Relenza Diskhaler's association with milk makes it the only option that should be avoided in this specific allergy context.