Explanation
The sentence sets up a contrast between reputation and reality. The conductor was "widely regarded as irascible and unapproachable" - irritable and difficult to deal with. However, the musicians who actually worked with him knew a different person: "a figure far more ______ than the legend suggested." The blank must mean the opposite of irascible and unapproachable - a word meaning friendly, warm, good-natured, or pleasant.

The correct pair must be tight synonyms that both describe a warm, agreeable disposition.
- A. perceptive - Having keen insight or understanding. While a conductor might well be perceptive, this does not directly contrast with "irascible and unapproachable." The contrast is about temperament (irritable vs. pleasant), not intellectual acuity. Incorrect.
- B. genial - Warm, cheerful, and friendly; affable. "A figure far more genial than the legend suggested" directly contrasts with "irascible and unapproachable." Correct.
- C. astute - Shrewd, perceptive, clever. Like "perceptive," this describes mental sharpness, not interpersonal warmth. It fails to contrast with "irascible." Incorrect.
- D. competent - Capable, skillful, effective. While musicians might value a competent conductor, "competent" does not contrast with "irascible." An irascible person can be highly competent. Incorrect.
- E. amiable - Having a friendly and pleasant disposition; good-natured. "A figure far more amiable than the legend suggested" produces a sentence virtually identical in meaning to the one with "genial." Both describe a warm, approachable temperament. Correct.
- F. efficient - Productive with minimum waste; effective. Like "competent," this describes professional capability, not personal warmth. It fails to contrast with the reputed irascibility. Incorrect.