Replying to Elusive or Illusive

Is a FS FS B2 an elusive or an illusive?
il·lu·sive
iˈlo͞osiv/Submit
adjectiveliterary
deceptive; illusory.
"that illusive haven"

e·lu·sive
ēˈlo͞osiv/Submit
adjective
difficult to find, catch, or achieve.
"success will become ever more elusive"
synonyms: difficult to find; More
difficult to remember or recall.
"the elusive thought he had had moments before"
synonyms: indefinable, intangible, impalpable, ambiguous
"an elusive quality"