Nathan, a civil engineer in a construction company, is one of the best performers in the organization. he is assigned challenging projects by his manager. he delegates low-risk tasks in projects and takes up the high-risk ones. in the context of mcclelland's learned needs theory, nathan is most likely motivated by the need for

Need for achievement

Explanation:

The people who are motivated for achievement are more challenging. These select the project that is more challenging but not impossible. These types of people focus on the problem so they can sort out and can achieve the target. The people who work on the need for achievement are effectively working and complete the task alone or in a group.  

There are some characteristics of this type of person.

Thus here Nathan a civil engineer in a construction company is the best performer because of his high need for achievement.  

where is the rest of the question. this isn't making sense. can you upload a picture of the question?