سوال ۲۹ کنکور ارشد ریاضی ۱۴۰۰

PASSAGE 3 (excerpt, paragraph 3):

"We may fairly lament that intuitive probability is insufficient for scientific purposes, but it is a historical fact. ... No intuitive argument has been offered why photons should behave differently from protons and why they do not obey the "a priori" laws. If a justification could now be found, it would only show that intuition develops with theory. At any rate, even for applications freedom and flexibility are essential, and it would be pernicious to fetter the theory to fixed poles."

29- Choose and mark the choice that is closest in meaning to the underlined word "essential" in paragraph 3.