None of the above
'69 COPO and Yenko Camaros pretty stomped all else at the track/strip. That would be my vote.
No 280zx during that time period either. 240z(69-73) or 260z(74) were great entry level sport/tourers. Had one, loved it.
Your poll has three and a half muscle cars (Smokey and Bandit TA's were weak) and one euro inspired Japanese sport/tourer. Weird. If your looking for the ultimate car during the period it's probably a Ferrari or Lamborgini. If your looking for the ultimate muscle car, see above. If you want to see a car that revolutionized the affordable compact roadster segment, look no further than the Z.
But to try and pick a winner is going to be tough.