In which of the following areas can GPS technology be used?1.Mobile phone operations2.Banking operations3.Controlling the power gridsSelect the correct answer using the code given below:

1. A

   1 only

   (a) 1 only. Mobile phones do use GPS/GNSS for location, maps and time, but banking timestamps and power-grid synchrophasors also rely on the same satellite clocks. Stopping at mobiles understates the spread. This option is not the key.

2. B

   2 and 3 only

   (b) 2 and 3 only. Banking (secure time-stamping, ATM/network sync) and grid control (PMUs, load dispatch) use GPS, yet phones are the most familiar civilian use. Dropping statement 1 is therefore wrong. This option is not the key.

3. C

   1 and 3 only

   (c) 1 and 3 only. Mobiles and grids are genuine uses, but so is banking. This option is not the key.

4. D

   1, 2 and 3

   (d) 1, 2 and 3. GPS supplies position and a precise time signal. Handsets navigate with it; banks and payment rails use GPS-disciplined clocks; power grids synchronise phasor measurement units to the same time. All three areas therefore apply. This option is the official key.

Summary. Official key is (d) 1, 2 and 3. GPS is a dual position-and-time utility. Mobile operations need location; banking operations need authenticated time; power grids need microsecond sync for protection and PMUs. None of the three listed areas is outside that utility. Partial codes that omit any one use are incomplete. The Set A key is therefore all three.