1989 Corvette, was on the way home coming down The highway. Went to give it a little gas, and it was nothing. kept trying but it was like the car was off it kept slowing down and slowing down. Pulled over to the side of the road it idled for a couple of seconds and shut off. Push the clutch in tried to restart it was barely a click all the dash lights were on. When I went to try it again there was nothing no power no electricity no nothing no lights and it did absolutely nothing. Any ideas on this. I'm wondering if it's the battery or if it's the alternator. Please assist.