The Vpu Protein from HIV Increases the Release of Newly

The Vpu protein from HIV increases the release of newly synthesized virus particles from the surface of infected cells.Which of the following describes the mechanism by which Vpu does this?

A) It degrades the sialic acid residues on the surface of the cell, which the virions can bind to.
B) It induces the degradation of the protein tetherin, which keeps the virions attached to the cell surface.
C) It increases the number of CD4 proteins to be exported to the cell surface.
D) It causes the plasma membrane to become flexible and fold around the budding virion.
E) It increases the export of gp120 and gp41 to the cell surface.