Vanessa: All computer code must be written by a pair of programmers working at a single workstation. This is needed to prevent programmers from writing idiosyncratic code that can be understood only by the original programmer. Jo: Most programming projects are kept afloat by the best programmers on the team, who are typically at least 100 times more productive than the worst. Since they generally work best when they work alone, the most productive programmers must be allowed to work by themselves. Each of the following assignments of computer programmers is consistent both with the principle expressed by Vanessa and with the principle expressed by Jo EXCEPT: ['Olga and Kensuke are both programmers of roughly average productivity who feel that they are more productive when working alone. They have been assigned to work together at a single workstation.', 'John is experienced but is not among the most productive programmers on the team. He has been assigned to mentor Tyrone, a new programmer who is not yet very productive. They are to work together at a single workstation.', 'Although not among the most productive programmers on the team, Chris is more productive than Jennifer. They have been assigned to work together at a single workstation.', 'Yolanda is the most productive programmer on the team. She has been assigned to work with Mike, who is also very productive. They are to work together at the same workstation.']