Magnitude range can be recorded by instruments but isn't felt

Magnitude range of 1 - 2.5

Explanation:

An earthquake of magnitude up to about 2.5 or less than that can not be felt, but it can be recorded by an instrument called seismograph.

A seismograph is an instrument that measures the intensity of an earthquake, the duration as well as the direction of the propagating waves.

The magnitude of an earthquake is obtained by using a Richter scale that ranges from 1 to 10, where a magnitude of 1 cannot be felt and do not cause any damage but a magnitude of 10 is extremely destructive.

Thus the correct answer is Magnitude range of 1 - 2.5

b would be the right answer

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