Infrared light is effective for detecting chemical erasures in handwriting due to the different absorption properties of inks. This method allows examination for original text that has been chemically altered. Other methods such as x-ray fluorescence are less useful for this type of analysis. ;
The most effective method for detecting chemical erasures in handwriting is infrared light, as it can reveal differences in ink absorption. Other methods like x-ray fluorescence and gamma radiation are not suitable for this purpose. Therefore, the correct answer to the question is option C: infrared light.
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