$8.$ The $\_\_\_\_\_\_\_\_$ process involves the addition of hydrogen to hydrocarbons in the presence of a catalyst. This process is used to produce $\_\_\_\_\_\_$ and improve the quality of $\_\_\_\_\_\_\_\_.$

$($Options: hydrocracking, isomerization, reforming; diesel, gasoline, kerosene; lubricants, heavy oil, asphalt$)$