No decision is when someone makes the decision for you. My coach made the decision for me to pitch in the game.
A reasonable decision is when someone weighs the options and makes the best possible choice. I weighed out the options and knew I had a better chance of striking out the batter with a fast ball.
A snap decision is when there is a decision made without weighing the options. The batter had no time to weigh the consequences and just swung.