Imagine you are writing an argument to convince others that gasoline-powered vehicles should be banned in favor of electric. which group of people would you likely have to work most to convince?

retired taxpayers
tractor-trailer drivers (i think)
state highway officers
gasoline manufacturers (not it)

The group of people which you will likely have to work most to convince are the GASOLINE MANUFACTURERS.
If gasoline powered vehicles become banned, then the gasoline manufacturers will be out of business and they will have to shut down, thus loosing their mean of livelihood. Thus, with this type of topic, one will have to do real hard work in order to convince the gasoline manufacturers. The other group of people listed in the other options have nothing to loose, that is why those options are wrong.