Answer:
The vague or unacceptable word in the following sentence is 'theirselves'.
B. theirselves
Step-by-step explanation:
A vague word is a word which is used in a sentence and which has no explicit use in the sentence. The word does not perform any function in the word. Also, if it gets omitted, there isn't any change or disruption in the sentence. The usage of the word is not clear and distinct. In the above sentence, the use of the word, 'theirselves' can be omitted as it is not making any use or clarifying any meaning to them.