Final answer:
Fluoroscopy enables the direct observation of x-ray images in motion and is identified by option d. For pregnant individuals, ultrasounds, option c, are the safest imaging technique due to their non-invasive nature and lack of ionizing radiation.
Step-by-step explanation:
The correct answer to the question "______________ is the direct observation of the x-ray image in motion." is d. Fluoroscopy. Fluoroscopy is a type of medical imaging that shows a continuous x-ray image on a monitor, much like an x-ray movie. It is used during many types of examinations and procedures to provide a live motion view of internal structures, which is particularly useful for guiding a variety of diagnostic and interventional procedures.
Regarding the safest imaging study during pregnancy, the answer is c. ultrasounds. Ultrasound technology is the least invasive of imaging techniques and uses no ionizing radiation, making it the safest option for monitoring fetal development and diagnosing potential issues during pregnancy.