In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Question: The antiviral tamiflu that is used against the bird flu virus acts:
Options: <1> Inhibiting viral neuraminidase. <2> Inactivating the viral protease responsible for the processing of capsomere precursors. <3> Preventing the decapsidation of viral particles. <4> Blocking the interaction of viral particles with their cellular receptor. <5> Altering the activity of the viral DNA polymerase.
1