(c) You have a program where 30% of its execution time is inherently sequential. The remaining 70% consists of 20 parallel threads. On a single core processor it takes 100 seconds to run. (i) What is the minimum time that it could take on a system with 8 cores? Explain and justify your answer. (ii) Give 3 reasons why, in practice, you might not reach this theoretical speedup. Justify your answers