One key difference between the work of Goddard and Hollingsworth in intelligence testing is that ...

One key difference between the work of Goddard and Hollingsworth in intelligence testing is that
 
  a) Goddard was primarily concerned with identifying individuals of lower intelligence, while Hollingsworth was concerned with identifying individuals with high intelligence.
   b) Goddard assumed that intelligence was a product of both heredity and environment, while Hollingsworth assumed that intelligence was primarily inherited.
   c) Goddard concentrated on identifying levels of intelligence in children, while Hollingsworth was primarily concerned with identifying levels of intelligence in adults.
   d) Goddard was interested in identifying the best environments for people at different levels of intelligence, while Hollingsworth primarily concerned with developed new and better measures of intelligence.