Who is the current President of the United States as mentioned in the text?

The correct answer highlights that Joe Biden is the current President of the United States. This information is based on the fact that he took office on January 20, 2021, following the 2020 presidential election. If the reference in the question provides data up to October 2023, then it confirms his ongoing role as president at that time. The other individuals mentioned in the options served in the past: Barack Obama was president from 2009 to 2017, Donald Trump from 2017 to 2021, and George W. Bush from 2001 to 2009. Therefore, only Joe Biden aligns with the current officeholder in the context given.