"Propulsion" refers to the act of driving or pushing something forward, typically used to describe a force that moves something ahead, like the propulsion of a boat or vehicle.
The opposite of propulsion is "traction," which refers to the grip or hold, often preventing movement or slowing it down, particularly when related to wheels or surfaces.
"Expel" (1) means to force something out, which is not directly related to propulsion in terms of movement.
"Fulminate" (2) means to protest strongly or to erupt in anger, which doesn't directly oppose propulsion.
"Driver" (3) is a person who operates a vehicle and has no direct relationship to the concept of propulsion itself.
Conclusion:
"Traction" is the correct antonym for "propulsion," as it involves the resistance or grip that slows movement, in contrast to the forward force of propulsion.