Explain to Your Patient the Steps,in Order,in the Formation of Hydrogen

Explain to your patient the steps,in order,in the formation of hydrogen peroxide,a toxin that will cause damage to living tissues.
1) Free radicals combine
2) Free radical formation
3) Cellular dysfunction and biologic damage
4) X-ray photons are absorbed by water

A) 1,2,3,4
B) 4,2,1,3
C) 2,1,4,3
D) 2,4,1,3