Because it was Dan's first time on horseback, the instructor gave him the most

horse.
literal
docile

erratic
gullible

docile

The instructor gave Dan the most literal horse.

To determine the answer to this question, we need to understand the meaning of the words and the context given in the sentence.

The word "literal" means taking words or phrases in their usual or most basic sense without any metaphorical or figurative interpretation. In this context, it does not fit as a potential answer because it does not describe a type of horse.

The word "docile" means easily trainable, submissive, or obedient. It is often used to describe animals that are calm and easy to handle. Given that it's Dan's first time on horseback, it would make sense for the instructor to give him a docile horse that is less likely to be difficult or hard to control. Therefore, "docile" seems to be a suitable answer in this case.

The word "erratic" means unpredictable, inconsistent, or irregular. It is the opposite of being steady or predictable. This word does not fit as a potential answer because it suggests a horse that would likely be difficult to control and therefore not suitable for a beginner.

The word "gullible" means easily persuaded or deceived. It is used to describe someone who is overly trusting or naive. Since we are talking about a horse and not a person, "gullible" does not fit as a possible answer.

Based on the given options and the context of the sentence, the most appropriate word to complete the sentence would be "docile."