Which of the following is a difference between skill variety and multitasking?

a$.$ Unlike multitasking, skill variety is one of the desired outcomes identified by Hackman and Oldham in their job characteristics model.

b$.$ Skill variety is the extent to which the work requires several activities for successful completion, whereas multitasking involves doing several tasks at the same time.

c$.$ Unlike skill variety, multitasking is one of the five characteristics of job design identified by Hackman and Oldham in their job characteristics model.

d$.$ More skill variety leads to a greater knowledge of results, whereas more multitasking leads to a greater feeling of personal responsibility for the work.