An experiment was designed to compare the efficiency of three types of teaching methods - traditional face-to-face instruction, hybrid (technology-mediated instruction), and completely online. A statistical course of three parts of comparable length was made available in three parallel sections for students' enrollment. Each section used a different method for course delivery, and students were assigned to a different section for each part of the course. At the end of each part, a test was administrated, and results were recorded.

a. What are the blocks in this block design? What is this type of block design called?

b. Can this study be conducted as a double-blind study? Why?

c. Explain how randomization within blocks could be incorporated into the study.