Answer : Toggle switch
A toggle switch is a switch that has just two positions. For example, light switches that turn a light on or off are toggle switches.
To switch from one setting to another. The term toggle implies that there are only two possible settings and that you are switching from the current setting to the other setting.
Ans: C
A ring counter is a type of counter composed of flip-flops connected into a shift register, with the output of the last flip-flop fed to the input of the first, making a “ring” structure and for each clock pulse, counter advances switch by one step like in sequential gating systems. So, it works similar as a Stepping Switch
https://www.geeksforgeeks.org/isro-isro-cs-2007-question-34/