Help with reinstalling Windows XP on Dell Dimension 2350.

The top one is the default since that is the original drive that came with the computer. 

https://www.dell.com/support/home/us/en/19/product-support/product/dimension-2350/manuals 

However-- you should not use XP on the Internet since it has been obsolete for a few years now and is not safe. MS has stopped issues any updates or security fixes. The 2350 is 16(!) yrs old now and really ready for the recycling bin. 

https://support.microsoft.com/en-us/help/14223/windows-xp-end-of-support