What sin caused our first parents to fall from a state of innocency?

The choice that reflects the correct understanding of the sin that caused our first parents to fall from a state of innocency is centered around the concept of disobedience to God's explicit command. The key event, as depicted in the biblical account in Genesis, is the act of eating the forbidden fruit from the Tree of Knowledge of Good and Evil, which God expressly instructed Adam and Eve not to do. This act of disobedience signifies a breach of trust and disregard for God's authority, which ultimately led to their expulsion from the Garden of Eden and the introduction of sin into the world.

Disobedience is fundamental to the understanding of original sin since it emphasizes the breaking of a covenant with God. The act did not merely result from a loss of faith or a desire for equality with God; rather, it was a deliberate choice that contradicted God's command. This choice illustrates the nature of sin as rebellion against divine authority, reinforcing the idea that disobedience to God has significant consequences.