28. The scheme uses data patterns of size 2 and encodes the 2-bit patterns as one signal element belonging to a four-level signal a. 4B5B b. MLT-3 c. 2B1Q d. none of the above 29. The scheme uses three levels (+V, 0, and -V) and three transition rules to move between the levels a. MLT-3 b. 4B5B c. 2B1Q d. none of the above 30. Analog-to-analog conversion is needed if the available bandwidth is a. band-pass b. low-pass c. both a and b d. neither a nor b 31. In single-mode fiber optic cable a. bandwidth is greater than multi-mode cable b. light travels in straight lin