Which of the Following Teachers Is Clearly Planning for Heterogeneous

Which of the following teachers is clearly planning for heterogeneous groups?

A) Mr. Lillburn goes home one evening planning to make a list of groups for his class. He will group all those of similar ability together so some students are not holding others back.
B) Mr. Franklin plans his group by looking at the make up of his students. He knows that the best grouping will allow for African American, Asian American, and Caucasian boys and girls who represent different achievement levels to work together.
C) Ms. Hulihan sends around a sheet of paper. Students are allowed to choose their group, but must not work with someone they have worked with in the past.
D) Mrs. Harris asks students to go down the row, counting from one to four. Students with the same number are grouped together. She feels this is the best way to prevent friends from using the groups for socializing.