Final answer:
The cause of Christian's burden falling off is believing in Christ's atonement.
Step-by-step explanation:
The correct answer is D) Believing in Christ's atonement. Christian's burden falls off when he believes in Christ's atonement. In the Christian faith, atonement refers to the act of Jesus Christ taking the punishment for human sins upon himself, thereby providing forgiveness and salvation to believers.
Through Christ's sacrifice on the cross, believers are able to have their sins forgiven and find redemption. It is through their faith in Christ's atonement that their burden of guilt and sin is lifted.
For example, in the Bible, in the book of Romans 8:1, it states, 'There is therefore now no condemnation for those who are in Christ Jesus.' This means that through belief in Christ's atonement, there is no longer guilt or punishment for believers.