Pool line is the manufacturer of a pool cleaning system that has been called by the pool construction industry, "the miracle we have waited a lifetime for." the cleaning system is very effective and recommended by all consumer magazines. the result is that 93 percent of all new pools have the system, and 94 percent of all pool owners buying replacement systems choose pool line. the relevant product market is: a. pool cleaning systems. b. pool supplies and equipment. c. cleaning equipment. d. none of the above.