What postfix expression the expression tree below represent?

$($A$)a+b*c-d$

$($B$)(a+b)****(c-d)$

$($C$)$ a b c d $+-*$

$($D$)ab+cd-**$

$($E$)$ None of the above

Which of the following instmction level parallelism mechanisms highly depends

on the compiler optimization but requires only a simple hardware?

$($A$)$ Out$-$of$-$order execution

$($B$)$ Branch prediction

$($C$)$ Superscalar

$($D$)$ Pipelining

$($E$)$ VLIW