Answer: b) achievement test.
Explanation:
Achievement test is the assessment in which learned knowledge, skill and information is evaluated through help of test.This determines the development of skill in a person.
According to the question,Gretchen is taking achievement test to assess and evaluate her learned knowledge and skill in field of data operations.
Other options are incorrect because judgement test, critical thinking assessment,aptitude and psychometric test does not defined learned knowledge ability.Thus, the correct option is option(b).