You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: BACK TO BUSINESS 
Clue: No-contract & pay as you go plans are selling points of this cell phone company started by Sir Richard Branson
virgin mobile

Category: SCIENCE & NATURE 
Clue: Developed by astronomer A.E. Douglass, dendrochronology determines age in this way
counting tree rings

Category: WHO THE "H" ARE YOU? 
Clue: He was White House Chief of Staff, Supreme Commander of NATO Forces in Europe & Secy. of State

haig