B.
For those that could not write (So most), they carried a seal around either on a necklace or otherwise that they could use to stamp with ink to signify 'signing' something.
its b ;
The Sumerians used cylinder seals as a way to sign their names and authenticate documents. These unique, carved cylinders rolled over clay tablets, leaving impressions that acted as signatures. Thus, the correct answer is B. a cylindrical seal.
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