(B). expiditious.
Explanation: The definition of expiditious, according to Oxford Languages, is "done with speed and efficiency". Comparatively, the definition of instantaneous is "occurring or done in an instant or instantly". When looking at both of these definitions, it's clear to see that they are the closest in meaning.
Option A, short-lived, doesn't make sense here. Plenty of things in life are short-lived, and being "instantaneous" doesn't exactly mean something is short-lived. Option C is a no-go, because "delayed" means the direct opposite of "instantaneous". Option D is the same; "long term" means nothing like the word it would replace. Therefore, the answer must be Option B: "expeditious".
