Most vaccines are derived from weakened or killed strains of the same virus that they prevent, unlike the derivation of smallpox vaccine from a different virus altogether.

(A) the derivation of smallpox vaccine from a different virus altogether

(B) smallpox vaccine, which is derived from a different virus altogether

(C) smallpox's vaccine, which gets derived from a different virus altogether

(D) when smallpox vaccine is derived from an altogether different virus

(E) the altogether different virus from which smallpox vaccine is derived



OA B

Source: GMAT Prep