I believe the correct answer is D. All of the above.
Bias means having a prejudice or coming to a conclusion just with standard information, although this might not be correct. In this case, the only information we have on Eva is her age.
Age stratification is dividing people in certain cathegories based solely on their age, and thus leading to discrimination towards the elders. This may also lead to Ageism, which is in fact the act of discrimination based on age.
