What is the role of recombinase in generating lymphocyte diversity? Please help

What is the role of recombinase in generating lymphocyte diversity?

   a )Recombinase splices RNA to produce variable transcripts.

   b) Early in B cell development, recombinase links one light-chain V gene segment to one J gene segment.

   c) Recombinase combines DNA from human and viral origin.

How does an antihistamine reduce allergy symptoms?

   a) An antihistamine blocks receptors for inflammatory chemicals released from granules within mast cells.

   b) An antihistamine kills mast cells, blocking an allergic reaction.

   c) An antihistamine binds pollen antigens, preventing them from provoking an allergic reaction.