In this task, you are given a context paragraph of the tweet and question. Your task is to generate right answer of given question based on given context tweet paragraph.

Context: Vets saw a fetus on Mei Xiang's ultrasound today. Paws crossed 4 viable pregnancy #PandaStory National Zoo (@NationalZoo) August 19, 2015 Question: what type of medical imagery was used?
ultrasound.