Which motivation would McClelland say was the major need driving Blake Mycoskie to continue to work so hard despite being worth millions of dollars?

ACHIEVEMENT method of motivation.

Explanation: McClelland Achievement theory explains that an individual has three main motivators. They are, the need for; power, achievement and affiliation.

An individual that continues to work so hard despite being worth millions of dollars is likely to be driven by the ACHIEVEMENT factor of motivation.

The Achievement method of motivation illustrates the relationship between an individual's distinguishing feature and their need to succeed.

i have to go with a for this one