There are three conditions for a unit to recruit employees: first, rich knowledge; Second, skilled; Third, be hardworking. There are four job seekers who meet at least one of the conditions: A, B, C and D. It is known that: 1. A and B are not all knowledgeable; 2. A and D have the same level of knowledge; 3. C and D have the same degree of hard work; 4. Three of the four are knowledgeable, two are hardworking and one is skilled.
After assessment, the unit found that only one of them met all the conditions. Should he be?
A