Gen 2:15-18
15 GOD took the Man and set him down in the Garden of Eden to work the ground and keep it in order.
16 GOD commanded the Man, "You can eat from any tree in the garden, 17 except from the Tree-of-Knowledge-of-Good-and-Evil. Don't eat from it. The moment you eat from that tree, you're dead."

This wasn’t a “possibly” order, it was a clear consequence: “The moment you eat from that tree, you're dead." So there was no room for guessing.