Yearlings are horses that are between one and two years old, so I'd go for answer D.
According to search engines, the word underlined is yearling
Answer:
D. youth between 12 and 24 months old   Â
Explanation:
First, let's define all the options. A newborn refers to a person or animal recently born, of one or more days old, a trainee is someone or an animal being trained for a specific task, a foal is a young horse under one year old, and finally, a yearling is an animal, especially a horse that is between 12 and 24 months old, so D is the correct answer.
