What is the system reliability of a system comprised of four microprocessors (A, B, C, and D) connected in a parallel arrangement (active redundancy)? The reliability performance of each microprocessor is based on the exponential reliability distribution with the following failure rates: A = 23.5 × 10^-3 , B = 12.5 × 10^-4 , C = 12.5 × 10^-4 and D = 23.5 × 10^-3