P-trap location question?

Specific Inspection Topics Plumbing Inspections
1

Does the p-trap have to be directly under the the sink or with a home with crawl space can it be below the floor in the crawl?
I think not , but a plumber yesterday told me as long as it has one it is OK.

2

Maximum Distance

     According to the International Residential Code, the maximum vertical distance between the sink drain and the entrance to the p-trap is 24 inches. However, the Universal Plumbing Code stipulates that the total developed length of all tailpieces, arms and fittings connecting the drain to the p-trap must be 24 inches or less.
3

Thank! I thought it was something like that.