The question asks for the word opposite in meaning to the underlined word 'listless', as used in the sentence: "He found the musical rendition by the septuagenarian maestro to be listless."
'Listless' means lacking energy, enthusiasm, or spirit. It describes something dull or lethargic.
Comparing the options with the meaning of 'listless', the word 'scintillating' is the most suitable opposite. A scintillating musical rendition is full of life and excitement, contrasting sharply with a listless one.
Therefore, the correct antonym for 'listless' among the given choices is 'scintillating'.