sum :$=0$ for i $=1$ to $4$ for j $=1$ to i sum :$=$ sum $+($i $-$ j$)$ End$-$for End$-$for a$)$ For the iteration of the outer loop where i$=3,$ how many times does the inner loop execute? $(6$ points$)$ b$)$ How many times is the variable sum updated in total? $(7$ points$)$ c$)$ What is the final value of sum after the entire program runs? $(7$ points$)$