The Concept of Altruism Is a Difficult One Because

The concept of altruism is a difficult one because:

A) it is only a hypothetical construct
B) only self-rewarded behaviour can be considered altruistic and it is impossible to measure self-reward
C) it is almost impossible to ascertain whether a given behaviour was carried out without any anticipation of self-reward
D) it encompasses involuntary as well as voluntary behaviour
E) the concept is deeply mired in religious debate