Option 1 -> Benefit refers to an advantage or gain, not a prayer or blessing.
Option 2 -> Forgiveness means pardoning an offense, which differs from bestowing a blessing.
Option 3 -> Blessing is a prayer invoking divine favor or protection, directly matching benediction's meaning.
Option 4 -> Calmness refers to a peaceful state, unrelated to the religious or ceremonial act of blessing.
Hence, Option 3: blessing -> Benediction literally means "good speaking" (from Latin bene + dictio) and refers to a formal blessing or prayer, making "blessing" the precise synonym -> correct