Step 1: Understanding the Concept
Interferons are cytokines secreted by virus infected cells and some white blood cells.
Step 2: Function
They protect non-infected cells from further viral infection, forming part of the cytokine barriers in innate immunity.
Step 3: Match
The answer is interferons, option (B).
Final Answer:
Interferons are the cytokines released by virus infected cells.
\[ \boxed{\text{(B) }\text{interferons}} \]