Match the following

List $$-$$ $${\rm I}$$
$$A.$$ Commutation
$$B.$$ $$V$$ $$-$$ Curves
$$C.$$ Free wheeling diode
$$D.$$ Overlap

List $$-$$ $${\rm II}$$
$$P.$$ Resistive load
$$Q.$$ Inductive load
$$R.$$ Capacitive load
$$S.$$ Inter pole
$$T.$$ Source Inductance
$$U.$$ Synchronous motor

Referring to the figure the type of load is

A line - commutated inverter changes $$dc$$ voltage to $$ac$$ voltage

Thysistor circuits that directly convert poly phase $$ac$$ voltage from one frequency to another frequency are called _______.