According to the Job Characteristics Model, what best describes task identity?
选项：

A:the extent to which a job requires a variety of skills to carry out the tasks involved
B:the degree to which a job allows an individual to make decisions about the way the work will be carried out
C:the extent to which a person receives clear information about performance effectiveness from the work itself
D:the degree to which a job requires completing a "whole" piece of work from beginning to end
E:the extent to which a job has an important impact on the lives of other people