Ron Remembers Phil's Birthday,which Is in the Same Month as His,but

Multiple Choice

Ron remembers Phil's birthday,which is in the same month as his,but fails to recall Alex's birthday,which is in a different month.Though both of them are his friends,Ron's ability to recall Phil's birthday but not Alex's can be best explained through the concept of:

A) self-schema.
B) social comparison.
C) Schadenfreude.
D) individualism.