C is corrent. The requirement is to identify the purpose of a digital signature. C is corrent because the digital signature assures the recipient that the message came from a certain individual and it was not modified. A is incorrect because the digital signature does not assure that the message was sent to the correct address. B is incorrect because the digital signature does not provide assurance that the message was received by the intended recipient. D is incorrect because the digital signature does not assure that the message was not intercepted.
