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  1. Mathematicians have a distinctive sense of beauty: they strive to present
    their ideas and results in a clear and compelling fashion, dictated by
    as well as by logic.
    A caprice
    B aesthetics
    C obligation
    D methodologies
    E intellect

strive to present ideas/results in “clear” and “compelling” manner, dictated by ___ as well as logic
Using Math strategy, we can say that clear → logic and synonym for compelling in obligation

where is the blank in the question ?