What are the Death knight talent trees?

The three death knight talent trees are:
1. Blood - The blood tree focuses on heavy melee damage output and self-healing effects. Blood is generally referred to as 'the leveling tree' because it has zero downtime while grinding/soloing/questing. However, it is also likely to be the raid DPS tree of choice for endgame death knights.

2. Frost - The frost tree focuses on 'combo attacks' through the use of snares, rooting effects, and high burst damage via critical strikes. Frost is considered to be the primary tanking tree for the class, though both blood and unholy are capable of tanking as well.

3. Unholy - The Unholy tree focuses on damage-over-time effects, debuffs, area-of-effect abilities, and summoning spells. It is capable of both DPS and tanking just as blood and frost are, but focuses more on tanking magic-users and dealing damage through AOE attacks.