What is The Best adc to carry low elo?

I'd probably say Lucian since he can take care of himself.

Honestly, the answer is any of them. All the ADCs are strong enough to carry games in low elo, so just play the one you enjoy.

Any adc with some form of escape or self peel is good, since you usually can't rely on your team to peel for you in low elo unless you duo with your support.