Final answer:
The probability of not winning on a scratch-off lottery ticket with odds against winning of 3,294:19 is approximately 0.99 or 99%.
Step-by-step explanation:
To find the probability of not winning, we need to take the ratio of the number of unfavorable outcomes (not winning) to the total number of possible outcomes. In this case, the ratio of the odds against winning is 3,294:19. So, the probability of not winning is 3,294 / (3,294 + 19). Simplifying this expression gives us 3,294 / 3,313, which is approximately 0.99 or 99%.
Therefore, the correct option is (a) (19/3313).