Final answer:
The character known as Mario's 'son' in SuperMarioLogan is Jeffy.
Step-by-step explanation:
In the popular web series SuperMarioLogan, the character that can be considered as Mario's 'son' is Jeffy. Therefore, the answer to your question would be: A: Jeffy. Jeffy is a central character who is depicted as Mario's adopted son. Even though he tends to behave quite irresponsibly and immaturely in the series, his character is an integral part of the entertaining nature of SuperMarioLogan.
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