Final answer:
To confirm a diagnosis of placenta previa, an ultrasound exam is used as it is a safe and non-invasive method during pregnancy.
Step-by-step explanation:
The diagnosis of placenta previa is often confirmed through an imaging technique known as ultrasound exam. This non-invasive method is preferred because it uses high-frequency sound waves to create images of the inside of the body, making it safe for both the mother and the fetus. Procedures like laparoscopy, which can be used to diagnose conditions like endometriosis, are not considered safe during pregnancy due to the invasive nature and potential risks involved. The use of ultrasound not only aids in accurately diagnosing placenta previa but also aligns with the paramount concern for the well-being of both the expectant mother and the developing fetus. Therefore, the answer is D. Ultrasound exam.