Given This Hypothesis Answer the Following Two Questions

Multiple Choice

Given this hypothesis answer the following two questions. Middle school students in an urban school who are trained in discussion techniques perform better on written tests of persuasive essays than those students who are not trained in discussion techniques.
-The independent variable in the above stated hypothesis is:

A) Urban school.
B) Training in discussion techniques.
C) Persuasive essay tests.
D) Middle school students.