A research group is comparing the learning outcomes of students who are taught a lesson using four different teaching techniques. There are 75 students in the school who can participate in the experiment. Using a table of random digits, the researchers will randomly place the students into five equally sized treatment groups suitable for comparison, four of which will receive a different teaching technique and one of which will remain a control group. Which design is the most appropriate for this experiment?

A Randomly number each person with 1, 2, 3, 4, or 5. Assign the students to the treatment groups based on their label.
B Select a student, and identify the first digit reading from left to right on a random number table. If the first digit is 1 or 2, assign that student to the technique 1 group. Similarly, digits 3 or 4, 5 or 6, 7or 8, and 9 or 0 go with the technique 2, technique 3, technique 4, and control groups, respectively. Repeat this process for each student.
C Number each student from 1 to 75. Reading the numbers from left to right on a random number table, identify 60 unique numbers from 1 to 75. Assign the students whose labels are the first 15 numbers to the technique 1 group. Assign the students whose labels are the second 15 numbers to the technique 2 group. Repeat this process two more times to assign the technique 3 and technique 4 groups. Finally, assign the remaining students to the control group.
D Number each student from 00 to 74. Reading the numbers from left to right on a table of random numbers and looking at two digits at a time, identify 60 unique two-digit numbers from 00 to 74. Assign the students whose labels are the first 15 numbers to the technique 1 group. Assign the students whose labels are the second 15 numbers to the technique 2 group. Repeat this process two more times to assign the technique 3 and technique 4 groups. Finally, assign the remaining students to the control group.