Answer:
Correct answer is a. true.
Step-by-step explanation:
Holocaust is one of the greatest crimes committed in human history with a goal to erase Jewish population.
Although, Nazis tried to destroy the records of Holocaust, today we have many evidences that are leading us to conclusion that all these crimes were planned.
Prisoners in death camps were tattooed, so they would be differentiated between each other.
Mass graves that were found are showing us how great those atrocities were.