When changing the engine oil on a four-stroke motorcycle, why is it recommended to run the engine for a few minutes before draining the oil?

1. To warm the oil so it thins and drains quickly and completely, carrying out suspended contaminants
2. To increase the engine oil pressure so it pushes the oil out of the filter
3. To allow the oil filter to absorb any water before it is removed
4. To cool down the crankcase so the drain bolt is safe to handle