Doug explained his "a" in biology as being the result of hard work and intelligence. He explained his "d" in chemistry as being the result of "bad teaching." this is an example of

i believe the answer is: Self-serving bias

Self serving bias refers to the type of thinking that being done solely for the purpose of maintaining our personal self-esteem. So when we are evaluating things that happen to us, the only explanation that we can come up with self-serving bias would always portray us in positive light.