b) A manufacturing plant utilizes a set of identical centrifugal pumps to transfer cooling fluids. Over the past year, the plant has experienced sporadic failures of the pump motor drive assemblies, leading to unplanned downtime. The failure history data shows that the average motor drive mean time between failures (MTBF) is 4 months of 24/7 operation, and the mean time to repair (MTTR) is 120 hours. If the facility requires pump availability of 99% uptime per year to maintain production levels, calculate the number of pump and motor drive assemblies recommended to be installed with redundancy to achieve the 99% availability target, given the provided MTBF data.