Select the most appropriate option to fill in the blanks.

Hay provides the _________ of the horse's ration and may be of varying composition _________ locale. Mash is bran mixed with water and with _________ invigorating additions or medications. It may be given to horses with digestive troubles or deficient eating habits.

The most appropriate option to fill in the blanks is Option D.

“Hay provides the bulk of the horse’s ration and may be of varying composition according to locale. Mash is bran mixed with water and with various invigorating additions or medications. It may be given to horses with digestive troubles or deficient eating habits.”

This option makes the most sense in the context of the sentence, as it correctly describes the role of hay and mash in a horse’s diet. The word “bulk” refers to the largest part or most of something, so it accurately describes the role of hay in the horse’s ration. The phrase “according to locale” indicates that the composition of the hay can vary depending on the location. The word “various” in the context of the mash indicates that different additions or medications can be added to the mash.