A hybridoma is:

(A) A hybrid cell obtained by fusing a β–lymphocyte with a myeloma cell in vitro
(B) A hybrid cell obtained by fusing a β–lymphocyte with a myeloma cell in vivo
(C) A hybrid cell obtained by fusing 2 β–lymphocyte cells in vitro
(D) A hybrid cell obtained by fusing any 2 body cells in vitro