Which of the following contains a vague pronoun reference?

 - Moray eels look like snakes, but snakes belong to a different class of the animal kingdom.
 - Moray eels look like snakes, but they belong to a different class of the animal kingdom.
The second answer choice contains a vague pronoun reference. The pronoun they could refer to moray eels or snakes.
The first answer choice shows a possible correction for the vague pronoun reference. They has been replaced with snakes.
Moray eels look like snakes, but snakes belong to a different class of the animal kingdom.