Complex sentence: The name is thought to refer to the sound a baby makes; another, somewhat questionable theory is that the candy was sold at the Grand Ole Opry (GOO), except that the Opry was established in 1925,13 years after the candy's debut.
Split into simpler sentences: The name is thought to refer to the sound a baby makes. The candy was sold at the Grand Ole Opry (GOO), which was established in 1925,13 years after the candy's debut.