8. Set partitions. Find the exponential generating function for the number of set partitions of n element set where: (a) each block has size greater than or equal to 2 and there are exactly k blocks. (b) each block has size greater than or equal to 2. (c) each block has size is odd. (d) there is an odd number of blocks. 8. Set partitions. Find the exponential generating function for the number of set partitions of n element set where: (a) each block has size greater than or equal to 2 and there are exactly k blocks. (b) each block has size greater than or equal to 2. (c) each block has size is odd. (d) there is an odd number of blocks