(c) Consider the following piece of incomplete pseudocode: function SUM(n) a 0 while n > 0 do a+a+n n+MISSING end while return a end function When completed, this function should return the same values that RECSUM(n) returns for input parameter n. 1. What should go in the place of MISSING to complete this pseudocode? (1 mark) 2. Briefly explain why the worst-case space complexities of SUM(n) and RECSUM(n) are O(1) and O(n) respectively for input parameter n. (5 marks)