Some members of society consider eva to be a burden because she is 70 years old and no longer physically capable of working. what is this an example of? a. bias b. ageism c. age stratification d. all of the above

The situation stated is an example of b.Ageism. This is so because although they are all closely related to one another, ageism is the most specific among other choices. Ageism means prejudice based on the age of a person. This makes ageism a type of bias. Ageism is also an effect of the division of age groups or Age Stratification. 

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.