Answer:
Explanation:
If we look at the other two options, the numbering style have been used incorrectly. The numbers in the first option should have been written in numerals as there is a point decimal mentioned in the sentence.
Correct format: Mr. Yu predicted that 55.6 percent of his customers would return for follow-up services.
In the second option, the number should have been written is words as it denotes a single digit number. When there is a single digit number, it is normally written in words.
Correct format: My salary increased three percent last year.