Final answer:
Gabby Douglas trained with coach Liang Chow in West Des Moines, Iowa when she left her family at age 14. Chow is known for training Olympic-level gymnasts and helped Douglas win gold in the 2012 Olympics.
Step-by-step explanation:
At age 14, Gabby Douglas left her family to train in West Des Moines, Iowa with a renowned gymnastics coach. The correct answer to the question of who her coach was is b) Liang Chow. Liang Chow has been widely recognized for his expertise in coaching world-class gymnasts, including Gabby Douglas, who went on to achieve significant success in gymnastics, notably winning the all-around Olympic gold medal at the 2012 London Olympics.