$1.$ Which line$($s$)$ of this program define$($s$)$ the base case offun$()$ method? $(10$ points$)$

$2.$ Which line$($s$)$ of this program include recursivecall$($s$)?(10$ points$)$

$3.$ Trace the recursion below $($You must show the

trace step by step, otherwise no credit!$)(20$ points$)$

$4.$ At what step of your recursion tracing did you hit the base case? $(10$ points$)$

$5.$ What is the final output of this code? $(10$ points$)$