Final answer:
Ovaltine was the malted drink that was popular among children in the 1930s and '40s due to its sponsorship of radio programs like "Little Orphan Annie" and "Captain Midnight".
Step-by-step explanation:
The malted drink that was popular among children in the 1930s and '40s thanks to its sponsorship of radio programs like "Little Orphan Annie" and "Captain Midnight" was Ovaltine. This chocolate-flavored malted drink gained popularity for its nutritious qualities and was advertised as a healthy choice for children.