You can choose any three of the following elements.
Fire
Water
Earth
Wind
Lightning
Nature
Ink
Sound
Space
Illusion
Time
The Source*
* Denotes an element every character receives.
This means that they choose any of the three elements and on top of that they receive the The Source element. The Source element is essentially the, "Raw energy" element and will allow unaligned raw energy to be used as either shields, blasts, swords of raw nonelemental aligned energy and etc.
You are required to have 4 elements (The Source and three others of your choosing).