a) Best angle = least ground distance. Use this for short runways/trees at end etc.
b) Best rate of climb = use this for headwinds at low levels.
c) If no obstacles, no low level headwinds, add an additional 10+ knots (for a single) for most efficient a-b on fuel burn. Somewhat nicer on the engine too (more airflow over the jugs).
a) and b) are in the POH. c) is not taught but experienced.
Wait until you do formation flying... then for formation takeoffs you do Vwa(worst aircraft) less a fudge factor so they can remain in formation. First time you do derated takeoffs your brain is going "nooooooooooooooooooooooo".