Which type of fuel injection arrangement eliminates high-pressure fuel lines between the pump and nozzle by combining both components at each cylinder?

Why C is correct

In a unit-injector system the pump and nozzle are combined into a single assembly at each cylinder and actuated directly by the camshaft, eliminating the high-pressure lines and the injection timing lag associated with them. The pump-line-nozzle (jerk-pump) system uses separate components connected by high-pressure lines, and the common-rail system uses a shared accumulator.