Explanation:

- Statement 1: GPS indeed allows accurate time-stamping on ATM transactions. GPS satellites carry atomic clocks and provide precise time data. This timestamp ensures synchronization of transactions globally.

- Statement 2: GPS relies on a constellation of satellites orbiting the Earth. These satellites transmit signals that the GPS receivers use to determine location, velocity, and time. Without these satellites, the GPS system would not function.

- Both statements 1 and 2 are correct, supporting option 3.

Correct Answer: Option:3 i.e. Both 1 and 2