Three benchmarks (Programs) are used to assess the performance of 4 computers. The execution time results (in second) are given below: a- Compute the total execution time for each computer. b. Compute the arithmetic average of execution time for each computer. c- Sort the computers AD depending on their performance from the best to the worst. d- Given the Bench 1 has 100000000(108) instructions, compute the rate (MIPS) of computer A