Answer:
Lactobacillus bacterium.
Step-by-step explanation:
The new cells arise from the pre existing cell according to the theory proposed by Virchow. The organism mostly produces the new organism of its same kind.
Lactobacillus is the bacteria that belongs to prokaryotyes and has the simplest body organisation. The Lactobacillus divides to produce the new bacteria of its same kind. The simplest organism will be produced from the Lactobacillus among all the other options given in the question.
Thus, the correct answer is option (d).