Answer: B) Not an excessive incentive.
Step-by-step explanation:
According to the question,IRB(Institutional Review Board) should guide and monitor research by determining that toys are not excessive incentive as research subjects can lie or don't inform researcher about not meeting eligibility criteria so that they can be a part of research.
Other options are incorrect because educational aspect, high quality aspect and age consideration are not the aspects for toys that is required to be explained. Thus, the correct option is option(B).