D
Teacher: Students don' t need parental involvement to succeed. In my class of twenty kids, the two highest achieving students come from foster homes. There are too many children in the foster homes for their parents to monitor homework and enforce study habits. It' s always the case that students can overcome their parents' indifference. What mistake does the teacher commit in his reasoning?
A: The teacher fails to consider competing theories.
B: The teacher's conclusion is totally unjustified.
C: The teacher is biased.
D: The teacher relies on an unreasonably small sample size in drawing his conclusion.