Tacita is interested in how teachers' classroom management practices change over time. she conducts observations of 8 teachers' classrooms over the course of five years. she interviews the teachers and follows up with counts of referral data, disciplinary notes in children's files, and number of notes home per teacher per year. this study can be described as a
select one:
a. qual-quan study.
b. quan-qual study.
c. quantitative study.
d. quan-qual study.