Who first observed and thus hypothesized that new cells are formed from previously existing living cell?

(A) Theodor Schwann and Schleiden (X)
(B) Rudolph Virchows ()
(C) Louis Pasteur (X)
(D) Both b and c (X)

Answers: Who first observed and  thus hypothesized that new cells are formed from previously existing living cell Rudolph virchows.