Please help me decide

tepig

oshawott

snivy

Snivy

tepig

OSHAWOTT

oshawott but if you're trying to choose the best one strength-wise, then tepig

snivy is really bad in bw (and bw2) play throughs, to be honest. (and i dislike it as well)

i did choose snivy in my white nuzlocke that i have yet to finish but i've barely used it

THE BEST STARTERS FOR EACH REGION
kanto: bulbasaur
johto: cyndaquil
hoenn: mudkip
sinnoh: chimchar
unova: tepig
kalos: fennekin
alola: popplio, even though it's ugly and I hate it
galar: scorbunny

you are false for Kanto(it's Charmander) Hoenn (Torchic) and Alola(Litten)

yes but type advantage-wise