Multiplexers can be designed to handle various numbers of input variables, but practical limitations arise from the number of terminals on the chip. A 16:1 multiplexer can be created for two input variables, A and B, although this is not common. While multiplexers typically come as 1-bit slices, options for 2, 3, and 4-bit slices exist, though wider slices offer minimal advantages due to saved address decode logic. For implementing wider parallel bus multiplexers, tri-state, open collector, or open-drain outputs are recommended. Understanding these configurations is essential for effective multiplexer design.