Which event did Marjorie Gestring win a gold medal in?

Marjorie Gestring won a gold medal in 3m springboard diving at the 1936 Berlin Olympics. Her victory at such a young age, when she was only 13 years old, made her the youngest female athlete to ever win an Olympic gold medal at that time. The 3m springboard diving event showcases athletes' skills in precision, agility, and technique, all of which Gestring demonstrated effectively to achieve her Olympic success.

The other options listed do not correlate with Gestring's athletic career, as she specialized in diving rather than track and field events like the long jump, 100m sprint, or 80m hurdles. Her accomplishment is a significant historical moment in diving and Olympic history.