Name the device used to increase the voltage at the generating station.

Transformers are capable of either increasing or decreasing the voltage and current levels of their supply, without modifying its frequency, or the amount of Electrical Power being transferred from one winding to another via the magnetic circuit. So the current is sent through step up transformers to increase the voltage and to push the power over long distances.
A step-up transformer turns low-voltage electricity into high-voltage electricity while dropping the current. 
Hence, a step up transformer is used to increase the voltage at the generating station.Hence correct option is A