Final answer:
The first statement regarding the graphic rating scale is true, as it allows rating on a continuum of performance. Criticism of pay-for-performance schemes includes the potential to undermine teamwork, as it may emphasize individual achievements over group efforts.
Step-by-step explanation:
The graphic rating scale is indeed a method where the rater marks an employee's performance on a continuum indicating low to high levels of a particular characteristic, making the first statement (a) True.
Regarding the criticism of a pay-for-performance approach, while there are several potential criticisms, the correct answer related to the options provided is (b) It prevents teamwork in the workplace. This criticism is supported by the idea that a pure pay-for-performance approach may unduly emphasize individual achievement over collaborative efforts, potentially undermining team dynamics and cooperation.