In 1980, alfa romeo introduced the first system to smooth a rough idle caused by ignition and camshaft timing changes.

In 1980, Alfa Romeo introduced the first valve-timing(needs precise timing, for piston valves) system to smooth a rough idle caused by ignition and camshaft timing changes.

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.