Final answer:
The nurse's priority is to stimulate uterine contractions.
Step-by-step explanation:
The nurse's priority is to massage the client's fundus to stimulate uterine contractions (option C).
During labor, stretching of the myometrium and cervix by the full-term fetus stimulates nerve impulses to be sent to the brain. This triggers the release of oxytocin from the pituitary gland, which in turn causes uterine contractions.
The stimulation of contractions is necessary for the progression of labor and the eventual delivery of the baby.