Using C programming only please $2.$ You$$d think that you will get an A if your average is higher than $89\mathrm{.}5$ since we believe in $$Round$-$UP$,$ right? $.$ But unfortunately, it seems that computer only understands $$Round$-$Down$.$ Take for an example, the average of $83,91,$ and $95$ is $89\mathrm{.}7$ but the computer popped out $89\mathrm{.}00!$ How would you like to modify the script so we can have the real $$Round $$ up $$ effect $($such as $89\mathrm{.}7=>90$ and $89\mathrm{.}3=>89)$ can take place? DO NOT CHANGE VARIABLE TYPES AND SIGNIFIERS, PLEASE!

GIVE EXPLANATIONS ON YOUR METHOD as well!