Answer:
C) High voltage to low voltage
Step-by-step explanation:
At a power plant, there is a production of electricity at a high voltage compared to the voltage provided to our home.
Voltage of about 12 KV is produced by power plant which is then converted into about 400 KV or greater (depending upon the countries) to transfer electricity from power plant to city Grid station using Step-up transformer. At City Grid station, Step-down transformer is used to convert high voltage (about 400 KV) to low voltage (about 13 KV) to transfer electricity from grid station to the city. Then this low voltage (about 13 KV) again converted to 220 V using Step-down transformer for household usage. So, overall about 12 KV voltage at power plant is converted into 220 V for household usage using step-up and step-down transformer at different stages.