Final answer:
The nurse would assign a score of A. 0 to the serous discharge observed using the REEDA scale.
Step-by-step explanation:
The nurse would assign a score of A. 0 to the serous discharge observed in the postpartum woman using the REEDA scale. The REEDA scale is used to assess the healing and progression of the perineal area after childbirth. The score of 0 indicates that there is no redness, edema, ecchymosis, discharge, or approximation issues.