Answer:
"The sacramental grace that we receive in each sacrament is different"
Explanation:
Since every one of the sacraments has a different effect upon our souls, the sacramental grace that we receive in each sacrament is different, which is what "proper to each sacrament" means. So, for instance, as St. Thomas Aquinas notes in the Summa Theologica.
To take another example, when we receive the Sacrament of Confession, we also receive sanctifying grace.
