Which of the following statements is true pertaining to the commutation of SCR?

The correct answer is option 4):(Class-A commutation is also known as load commutation. )

Commutation of SCR:

• Commutation is nothing but the turn OFF method of an SCR. It is one method used to bring an SCR or thyristor from the ON state to the OFF state.
• We know that an SCR can be activated by using a gate signal toward an SCR when it is in forwarding bias.
• But SCR needs to turn off when required for power controlling otherwise power conditioning.
• The commutation techniques of thyristors are classified into two types: Natural Commutation and Forced Commutation
• Class A commutation of the thyristor is a type of forced commutation and is also referred to as Load Commutation. It is one of the widely used commutation techniques that mainly find applications in high-frequency operations. Hence option 4 is correct.
• Class B commutation is also called as Resonant-Pulse Commutation. It is one of the types of forced commutation
• Class-C commutation is also known as complementary commutation. Complementary commutation is also called voltage commutation, forced commutation, complimentary impulse commutation, or Class-C commutation. It is used in dc choppers and inverters. 
• The auxiliary voltage commutation is also called  “Impulse commutation”, or class D commutation.it uses an auxiliary SCR to switch the charged capacitor.