Final answer:
The sacrament that unites the receiver's suffering with the Passion of Christ is Anointing of the Sick. It offers comfort, courage, and connects the sick person's pain with Christ's sacrificial death.
Step-by-step explanation:
The sacrament that provides a grace to unite the suffering of those who receive it with the Passion of Christ is B) Anointing of the Sick. This sacrament is meant to offer comfort, peace, courage, and, if the sick person is unable to make a confession, forgiveness of sins. The grace received from Anointing of the Sick assumes a deep spiritual significance as it unites the sufferer's pain with the sacrificial death of Christ on the cross, which is a central element of Christian theology, commemorated annually during Holy Week.