A maglev train uses powerful magnets to lift the train above the tracks as it moves forward. Such a design reduces what following force.

A rolling friction

B gravity

C air resistance

D fluid friction

They use magnets

A. Rolling Friction

Explanation:

Maglev is train transportation that uses magnets. Maglev will have two sets of magnets, the function of the first set of the magnet is to repel and push the train and lift the train from the track and the function of the second set of the magnet is to elevate the train further. In this process, the lack of friction is the main advantage. Guideway is the magnetic coil running along the track and it repelling the big magnets present on the undercarriage of the train. This repulsion causes the train to go up by 1 to 10 centimetres above from the guideway. All the maglev trains are floating on the magnetic cushion and it reduces the rolling friction.