Sentence that uses a formal writing style is:
2)A recent court ruling about compensation for college athletes has the potential to drastically alter college sports.
Step-by-step explanation:
The use of formal language is first of all evident in the direct nature of the sentence following a format without the expressive use of language which is evident in all other sentences in option.
It can be seen that the first sentence talks about people and gives an opinion which is also the case in the third and fourth sentences which are opinionated meanwhile the second sentence is informational and conveys the point effectively without bringing in any other information than the bare minimum necessary.