Which SAT scores to send?

I am currently a senior, and these are the scores I consider sending

Nov 2015: 2220 (800M/ 660R/ 760W/ 10E)
Jan 2016: 2250 (780M/ 710R/ 760W/ 10E)
Dec 2016: 1550 (800M/ 750E-- 38R/ 37W–/ 20E)

Which scores should I send to Princeton (and other colleges as well)?

All of them. There isn’t a bad score there. Send them all. Congratulations on fulfilling the test score requirement - now finalize the dickens out of your essays and enjoy your senior year.

Thanks!