What kind of effort is required to "attain" a high level of skill?

To "attain" a high level of skill implies that significant effort and dedication are necessary. The term "attain" conveys the idea of reaching or achieving a particular level, which usually requires consistent practice and hard work. Therefore, the phrase "consistent and diligent" aligns perfectly with the requirements of mastering a skill, as it highlights the importance of ongoing efforts and a serious commitment to improvement over time.

Other options suggest a lack of sufficient effort: "minimal and effortless" implies an easy achievement, which contradicts the notion of proficiency; "negligent and careless" indicates a disregard for quality and focus, while "brief and infrequent" suggests sporadic effort, neither of which would lead to high skill levels. Thus, the requirement for ongoing and dedicated practice solidifies "consistent and diligent" as the most appropriate choice when discussing the attainment of skill.