In order for a radiograph to have an IQI sensitivity of 2-2T or better:

The radiographic procedure must be able to differentiate a 2% difference in specimen thickness.

The radiographic procedure must be able to define the 2T hole in an IQI that is 2% of the thickness of the specimen.

The radiograph must be able to distinguish a discontinuity with a length equivalent to 2% of the specimen thickness.

None of the above.