Task: Explanation
Input (English): Chad Gray (born October 16, 1971), is the lead vocalist for the groove metal supergroup Hellyeah and former lead vocalist for American heavy metal band Mudvayne. Question: On which group is this artist, who signed and numbered the lithograph for the pre-ordered album "By the People, for the People," currently a vocalist? Answer: Hellyeah
Output (English): Chad Gray born October 16, 1971, is the lead vocalist for the groove metal supergroup Hellyeah and former lead vocalist for American heavy metal band Mudvayne.