| What is the purpose of the devices labeled "F SW" on the illustrated switchboard drawing? |
| A) to determine the individual frequencies of each leg of a three phase alternator output to be displayed on the frequency meter by selective switching |
| B) to determine the difference between the individual frequencies of each leg of the three phase alternator output to be displayed on the frequency meter by selective switching |
| C) to select which alternator frequency is to be displayed on the frequency meter |
| D) to determine the average frequency of individual frequencies of each leg of a three phase alternator output to be displayed on the frequency meter |
