The correct answer is: between.
The word “nexus” means a connection or link between two or more things. In the context of the sentence, the word “nexus” is used to describe the connection between politics and sports in India. The sentence suggests that there is a close relationship between these two areas, and that this relationship is often negative or harmful.
The other options are not as accurate or appropriate in this context. The word “with” could be used to describe a relationship between two things that are not necessarily connected, but it does not convey the sense of closeness or negative impact that is implied in the sentence. The words “among” and “by” are not appropriate in this context because they do not refer to a relationship between two things.
In conclusion, the correct answer is “between” because it is the most accurate and appropriate word to describe the connection between politics and sports in India.