Final answer:
K. Warner Schaie studied the development of cognitive abilities across the lifespan, focusing on verbal meaning, spatial orientation, inductive reasoning, number ability, and word fluency, as correctly listed in option A.
Step-by-step explanation:
K. Warner Schaie's cross-sequential research on intellectual development studies components of human cognitive function as individuals age. Specifically, Schaie's research looks at changes and consistencies across different age groups concerning certain cognitive abilities. The choices given relate to several aspects of cognitive functioning that are typically examined by psychologists, including verbal meaning, spatial orientation, inductive reasoning, number ability, and fluency in language use.
After reviewing the given options and considering the areas of cognitive function generally tested, option A appears to correctly list the five areas Schaie focused on in his studies: verbal meaning, spatial orientation, inductive reasoning, number ability, and word fluency. These measures of cognitive abilities are critical in understanding how intelligence may develop and change over a person's lifespan. Schaie's work underscores the importance of these cognitive domains in the broader context of aging and intellectual development.