when one wants to reduce the execution time

when there is a loop with a function call inside

when a function is called in many places in a program

both when one wants to reduce the execution time and when there is a loop with a function call inside

Sum:=N+Sum(N)

Sum:=N+Sum(N-1)

Sum:=(N-1)+Sum(N+1)

Sum:=(N-1)+Sum(N-1)

Non-recursive call

Recursive function call

Use of more external variable

None of these

Carnot ′s function

Rickmaan function

Both (a) and (b)

Ackermann ′s function

Are initialized during each execution of the function

Are retained from the last execution

Are maintained in a queue

None of these