The statement that is true regarding the deportation and mass killing of Armenians is:
Deported Armenians experienced starvation, violence, and disease.
This reflects the historical realities faced by Armenians during the deportations and massacres, particularly during the Armenian Genocide from 1915 to 1923. The other statements contain inaccuracies: mass killings began in 1915 and the evidence widely supports the characterization of these acts as genocide. Additionally, conditions in concentration camps were generally not better than those faced during deportation marches.