Studying the relationship between parental supervision and juvenile delinquency, Maria found a ...

Studying the relationship between parental supervision and juvenile delinquency, Maria found a strong relationship between the two. She then introduced a third variable, education, and the partials still showed a strong relationship between supervision and delinquency. What may she conclude?
 
  a. replication.
  b. that the relationship between supervision and delinquency is spurious.
  c. that the relationship between supervision and delinquency is nonspurious.
  d. that the relationship between supervision and delinquency is spurious and replication took place
  e. that the relationship between supervision and delinquency is nonspurious and replication took place