alternator question re: plug

ASSISTANCE Stock Engine-Bay Components
1

Hi there,

My battery light comes on when the car is started, but doesn’t go off while driving. I’m thinking my 3 y/o rebuilt Champion alternator is on its way out. I found a guy selling some tested ones for 40-$ but he has 2 types, 3 wire oval, and 4 wire round.

See here,

http://hamilton.kijiji.ca/c-cars-vehicles-parts-accessories-honda-acura-ls-rs-gs-gsr-sir-typer-motors-trannies-rimsswap-part-W0QQAdIdZ131220411

Which one would I need? I have a 91 LS stock 5 spd. I cannot tell by looking; I can’t even get my hand down there.

Thanks for your help.