His action was alternately vivacious and sullen. his voice varied rapidly from a tremulous indecision (when the animal spirits seemed utterly in abeyance) to that species of energetic concision—that leaden, self-balanced and perfectly modulate guttural utterance . . during periods of his most intense excitement.

which short story element does poe develop in the excerpt?

a. characterization
b. plot
c. setting
d. conflict

A) Characterization.

Explanation: Characterization is a literary device that is used to highlight and explain the details about a character in a story. In the given excerpt we can see an example of the use of characterization, because Poe is describing some of the character traits, like his actions, his voice ("...varied rapidly from a tremulous indecision...to that species of energetic concision"), and part of his personality by describing how he responds to being excited.

it was surely an odd creature that one made up by reading the historians first and the poets afterwards a worm winged like an eagle; the spirit of life and elegance and charm,   in a kitchen chopping up suet. but these creatures, monst'r however entertaining to the imagination, hast no existence in fact. what one might doth to bringeth h'r to life wast to bethink poetically and prosaically at one and the same moment,   thus keeping in toucheth with fact—that the lady is mrs martin, ag'd thirty-six, did dress in blue, wearing a black coxcomb and brown shoeth; but not losing sight of fiction eith'r—that the lady is a vessel in which all s'rts of spirits and f'rces art coursing and flashing p'rpetually. the moment, howev'r, yond one tries this method with the elizabethan mistress, one brancheth of illumination fails; one is did hold up by the scarcity of facts.   one knoweth nothing detailed, nothing p'rfectly true and substantial about h'r.   hist'ry scarcely mentions h'r.   and i did turn to professeth'r trevelyan again to seeth what hist'ry meanteth to that gent.   i hath found by looking at his chapt'r headings yond t meanteth.