Option 1: 1 Tesla - This is not the correct answer. The Earth`s magnetic field is not as strong as 1 Tesla.
Option 2: 2 Gauss - This is also not the correct answer. While the Earth`s magnetic field is measured in Gauss, it is not exactly 2 Gauss.
Option 3: 104 Tesla - This is not the correct answer. 104 Tesla is an extremely strong magnetic field, much stronger than the Earth`s magnetic field.
Option 4: 1 Gauss - This is the correct answer. The Earth`s magnetic field is typically measured at around 0.5 to 0.6 Gauss on the surface. Gauss is a unit used to measure magnetic field strength, and 1 Gauss is a reasonable approximation for the Earth`s magnetic field.