Question 15 The reason that we need to call fflushO or cinJgnore) is because the previous O A output function ailed to complece its operation O B.output function left a character in the file buffer O C.input funetion left e printable character in the file buffer D.input function left a new line character n' in the file buffer Question 16 n Cic, i the call-by-address parameter passing mechanism is used, whar is passed to the formal paramerer? OA The value of the actual paramecer B. The actual parameter itse(alas) C. A global variable. D.The address of theacual paramece Question 17 In C/C++, if the call-byvalue parameter passing mechanism is applied, the A.name of the actual paramezer is associated with the location of the formal parameter B.accual paramecer becomes an allas of the formal paramecer C. value of the actual pararmeter is copied into the location associated with the form parameter D..ddress of the actual parameter i passed to the formal parameter. Question 18 1 points In a recursive funetion, if a reaursive call separaces te body of the function into two pares and the part 1 ieracesnimes, then part A zero smes B. more tan ero but less than n times C exacty n times Question 20 Given the recursive function, answer the following fve (5) questions oD.more chan n simes // Line 1 int 1 3 1, If Cn"-1) return Line 2 Line // Line 4 // Line S Question 19 The time complexity of mergesort agorithm is foo(A,-2) // Lann while (