Final answer:
The nurse should identify the client statement 'The bleeding is bright red and painless' as indicative of placenta previa. Other symptoms may include frequent contractions, but a constant dull ache in the lower back is more commonly associated with preterm labor.
Step-by-step explanation:
The nurse in the emergency department should identify the client statement 'B. The bleeding is bright red and painless' as indicative of placenta previa. Placenta previa occurs when the placenta partially or completely covers the opening of the cervix, leading to painless vaginal bleeding. Other symptoms of placenta previa may include frequent contractions, but the statement about having contractions is not indicative of placenta previa. A constant dull ache in the lower back is more commonly associated with preterm labor.