Answer:
Option D
Explanation:
(D) The use of the conjunction 'but' implies the existence of a contradiction within the sentence. Monomania means obsession, to the point of madness, with a single task or in any person. But the use of the conjunction but implies that the author of the sentence does not consider Murray's monomania as harmful. So the missing word must have a positive connotation. We can therefore eliminate the choices same (meaning cowardly), tendentious (meaning dishonest) and meretricious (meaning goudy). The statement "his innocuous (meaning harmless) one" does not make any sense. The phrase, "His monomania must be regarded as a beneficent or at least an innocuous one" makes eminent sense. So, (D) is the answer.