The state Department of Public Instruction (DPI) would like to sample high school mathematics teachers to complete a survey on teaching methods. Among high school teachers some are National Board Certified (NBC) Teachers. DPI would like to talk to at least 100 of these teachers. Below are several proposed methods of obtaining this sample. For each, state which type of sampling method was used. The researcher from DPI will go to the 10 closest high schools to the DPI central office. At each high school she will talk with all the mathematics teachers at that location. The researcher will compile a list of all high school mathematics teachers in the state. She will number this list and use a random number generator to pick 100 teachers. The researcher will compile a list of all high school mathematics teachers in the state. She will divide the list into NBC teachers and non-NBC teachers. She will number these two lists and use a random number generator to pick 50 NBC teachers and 50 non- NBC teachers. The researcher will randomly select 25 high schools from a list of all high schools in the state. She then goes to each high school and talks with all the mathematics teachers at those high schools. The researcher will compile an alphabetical list of all high school mathematics teachers in the state. She will divide the list into those with last name starting with the letters A through K and those with last names starting with L-Z. She will number these two lists and use a random number generator to pick 50 from the A-K list and 50 from the L-Z list. The researcher creates a website that has the survey on it. She then sends a poster to all high schools in the state asking mathematics teachers to go online and fill out the survey. Choose... Cluster sampling Volunteer response sampling Systematic sampling Stratified sampling Simple random sampling Convenience sampling Stratified sampling Choose... Choose... Choose... "