$24.$ Which process in petroleum refining is primarily aimed at removing sulfur compounds?

A$)$ Cracking

B$)$ Reforming

C$)$ Alkylation

D$)$ Hydrodesulfurization

$25.$ The process used to convert straight$-$run gasoline into higher$-$octane gasoline is:

A$)$ Polymerization

B$)$ Isomerization

C$)$ Alkylation

D$)$ Catalytic reforming

$26.$ What is the primary goal of the petroleum refining process?

A$)$ To reduce the carbon footprint of petroleum

B$)$ To separate crude oil into usable fractions

C$)$ To increase the sulfur content for industrial use

D$)$ To solidify all petroleum products for easier transportation

$27.$ What is the main environmental concern associated with the use of high$-$sulfur fuel oil?

A$)$ Ozone depletion

B$)$ Acid rain

C$)$ Global warming

D$)$ Ocean acidification